They're rather unlikely to be the same tank. The bottom photo has all those "bumps" on the right-hand side cupola, as you're looking at the photo. (It's the commander's cupola, I think.) Upon inspecting a high-res photo on Wikipedia of a T-55, those bumps are bolts that hold the cupola in place.
Those are absent in the top photo of the meme. (Below is a slightly higher quality version than in the meme, after I tracked down where the original photo appeared--see end of post for source/link.)
Possibly those bolts were later replaced with a welded-in-place cupola as in the top photo in the meme, but it seems expensive to do just that modification to a tank and not e.g. install explosive-reactive armor and so forth. So the bottom tank in the meme photo is more likely a later-series tank.
FWTW, the bolted cupola does match tanks from other photos of the Budapest invasion.
Checking out some details in Zaloga's book on the T54/55, it appears (pp. 13-15) that the bolted cupola was present in the original T-55, while the welded version showed up in the T-55A, which had improved nuclear & chemical protection. Cupola detail of the latter below (from the book):
There's an interesting construction detail on the T-55A: only the vertical lower half of the cupola is actually welded the turret. There are in fact (smaller, visible in hi-res) bolts on that cupola too.
In a top-view you can see the small bolts more cleary, and the fact that this is only a partial cowling that is hiding... the original big bolts. (The latter photo is also in Zaloga's book.)
I suppose this would have made conversion from T-55 to T-55A (even) easier turret-wise. I'm not sure if there were conversions between the two models though. The book doesn't explicitly mention that. But it would have made some [more] to sense make that modification to existing tanks, given its purpose was more than replacing the cupola attachment system. So this [physical difference] is less conclusive than I first thought.
But Zaloga mentions (p. 15) somewhat generally that
Capital rebuilding often included an effort to upgrade the tank to a higher production standard with new features that had been developed in the intervening years. These rebuilding programs changed many details on the tanks, and makes it very difficult to identify the specific type of tank. [...] Tanks often underwent several capital rebuildings adding layer on layer of changes and making it even harder to categorize its precise model.
It also mentions though (p. 16) that by 1972 there were still in service T-55 (and T-55A) tanks with both kinds of cupolas (i.e. some had NBC, but some still didn't), enough of each than when the (DShKM) anti-aircraft machine gun was added [in these rebuilding programs], they had to design two kinds of fitting rings for it.
Reactive armor was only added to this series starting in 1985 [p. 34], so it's possible some mothballed and reactivated T-55 would not have it. I checked a few photos and videos claiming to show T-55s being sent to Ukraine, and they seem to be of this variety (no reactive armor, but 55A (NBC) style cupola. So the top photo in the meme at least matches some other recent claims, construction-wise. There's also footage of FPV drones hitting T-55 tanks that have that top screen as in the photo. So it seems plausible/authentic enough in that regard. Although there's no footage of its moment of demise (only aftermath photo), the "320" marked tank was reportedly photographed like that in August 2023, in case somebody wonders about the surrounding foliage.
I also found larger photo of the "320" tank used in the invasion of Budapest, on alamy. So that too is very likely a genuine photo. (Not gonna inline it here because stock photo companies love to sue.)
There's one more detail in the Budapest photo: the dome shaped fume extractor on the left side of the turret, in front of the gunner's hatch. That detail points to a T-54 model, rather than a T-55.
Alas, that part of the tank is not terribly visible in the Ukraine "320" tank. But on a museum T-54 that's photographed from the left side, at ground level, so in rather similar circumstances to the Ukraine 320, you can see (albeit just a wee bit) the dome ventilator, protruding over the turret. (There's unfortunately a radar in the background too, which somewhat confuses this picture.)
A photo from a somewhat similar angle of a T-54 being transported by rail somewhere in Russia (apparently in 2023), with annotations for identification, incl. one for the dome-covered turret fan, which is less visible though due to the extra elevation of the railcar.
This one has a bore evacuator (also seen in T-55s) which [in theory] makes the turret-roof-fan redundant, but the latter (or at least the cover thereof) is preserved nonetheless. Interestingly, they also have a photo of a "T-54B modernized from a T-54 M1951" (from the same transport), which does not spot the bore evacuator, but has a simple/shorter muzzle counterweight in its place. The angle of this latter photo, from behind the turret doesn't allows us to see the turret fan cover though--it's entirely obscured by the commander's cupola in that photo. The identification appears to have been made based on the lack of bore evacuator.
Also, in the (aforementioned) footage posted by Russian troops of their training with T-55s in/for Ukraine, we can see their tanks from that (left) side too. And they lack the dome-shaped fume extractor.
So all that suggests the "320" from Ukraine probably lacks the dome ventilator too, unlike the one from Hungary. (The FPV-hit T-55 is shot from its left-side too, but the video is very blurry to make much detail.)
I've been trying to find if any modifications of the T-54 managed to get rid of that little ventilator dome, but apparently no. Even Vietnam's highly modernized T-54s, which have a lot western optics, ERA, etc., still have that ventilator dome visible.
Wikipedia does mention that there was a "T-55LD - Polish T-54 tanks rebuilt to T-55A standard. 200 T-54 tanks have been rebuilt in 1975." But there's not much indication the USSR would have done something similar or that those would have been imported to the USSR. There are some mentions of those being exported to various African countries. I've yet to find a hi-res photo of this fabled T-55LD turret-wise. There's a small, blurry one on Wikipeidia.