You might be better served posting this question on the ptc discussion forum.
Seeing how Windchill is there product.
When I went to a rollout for windchill a couple of years ago, I know the company I was
at used Solidworks 2010 and Windchill was able to check in SW files very nicely.
So I would think the latest version of Windchill would do the same for SW 2012.
In our experience (we have both SW and WIndchill, but don't use them together), The SolidWorks add-on for Windchill is almost always 6-12 months behind the latest release of SW. So for SW2012 which was released last fall, the Windchill add-on will probably be released some time this summer or fall.
I refuse to delay the rollount of SW just to appease the Windchill folks here...And believe me, to hear the Pro-E guys complain about WC (which is a NATIVE Pro-E package), I can't imagine it would be any less painless with SW.