Well on this site http://www.davidsonsinc.com/consumers/subsites/dealer_home.asp?dealer_id=62832 you can search guns by caliber. It lists both .308Win and .308 so I assumed (I know) that they were different calibers.
But don't take it from me -- I would call them and ask what the difference is. It's their website. And please let me know what they say.
Depending on platform, the .30 cal round has an almost ideal profile for accuracy from 100-1000yrds with the .308Win bullet/powder/case combo being widely awknoledged as the most accurate.