First, I'm just going to say that there are several of studies on this topic from J.E. Leighley and J. Nagler that breaks down differences in voting turnout on several different factors (as well as dozens more by other authors). I'm providing this information for comprehensiveness, rather than to answer this specific question directly, because the issue is certainly multifaceted. Below is a small selection of these articles for the interested reader.
Individual and systemic influences on turnout: Who votes?
Leighley & Nagler, 1992
Socioeconomic class bias in turnout, 1964-1988: The voters remain the same.
Leighley & Nagler, 1992
Unions, voter turnout, and class bias in the US electorate, 1964–2004.
Leighley & Nagler, 2007
Specific to your question though, the best resource I can find is this:
Who Votes Now? And Does It Matter?
Leighley & Nagler, 1007
The authors analyzed the NAES data from 1972 and 2004 to detect changes in voter turnout. They do not provide data on statistical significance, but does display mean differences for various beliefs, attitudes, and associations between voters and non-voters. Given the sample size of most of the analyses (N >= 1000 for most analyses), we can assume that most mathematical differences greater than 3-5% are also statistically significant in the population (if one feels this assumption is inappropriate, I would be happy to run some analyses when I have a bit more time). This assumes, of course, that the NAES sample is representative of the population which I cannot verify conclusively (but its longevity supports this assumption).
As for the findings provided, there does appear to be differences and they can be seen in their entirety in the tables from page 24 through 28 in the linked pdf. To summarize these tables indicate a difference between political affiliation and voting behaviors such that voters tended to have strong republican or democratic affiliations (e.g., 20% of voters were strong republican v. 4% of non-voters, 6.5% of voters were independent v. 21% of non-voters). As far as attitudes on specific issues, there do appear to be some systematic differences but the directions are varied. Some examples include:
- 51% of non-voters v. 44% of voters prefer government run health insurance
- 32% v. 19% of non-voters believe that abortion should always v. never be legal, while the distribution for voters is 39% v. 12%
- 73% of non-voters v. 60% of voters favor unions.
- 68% of non-voters v. 50% of voters favor recalling troops from Iraq.
So to answer your question in the most general sense. No, non-voters and voters do not have identical distributions of viewpoints.