Quick question for you guys. I've got a 1990's production Winchester Model 70 in .308 that I would like to add a picatinny base to. I noticed when looking at Leupold Backcountry picatinny bases, the one I could find says "Winchester Model 70 SA-Post 2001". Yet EGW, for example, makes no distinction in their bases for pre or post 2001. Did Winchester change something in 2001 that I need to be aware of when ordering a base? Appreciate the help.