OK, I understand the caliber (30) but will a .308 round fire out of a .308 Win rifle and vis versa? When I called Wain Roberts they said that they are different rounds and that certain guns called for either .308 or .308 Win.
Nope. Same round. The NATO designation is 7.62x51. Wikipedia article isn't bad.
You'll find some mil-sup brass that has a thicker base section on it and a slightly different neck sizing on it that could cause problems with finicky platforms that have been highly "dialed in". SAAMI spec gages will show the difference, but for a standrad hunting rifle, you'll never notice a difference. For most .308 battle rifles, like the FAL, it'll eat pretty much any .308 round you feed it.
If you are setting up a bench gun, sniper rig, or extreme accuracy rifle, you'll be sizing and trimming your own brass to the .0001+/-" anyway and the mil-surp thick brass can actually be re-loaded more times without failure of the case. If you are shooting factory brass, you won't get peak accuracy out of your set up. Again, assuming a ton of variables.
Google it up. There are tons of articles out there.