what do you mean? 1302 also appeared to be GM. either 1308 *IS* the GM or it is not. Bugs can still appear - even in a GM, especially if it's from Microsoft.
People are talking about that 1308 is b14, which would seem a bit strange, for the bxx string used to go with the build number, i.e. b11 was build 11xx, b12 was build 12xx etc. so 1308 would just be a newer b13 than 1302. but we'll see when we get the packages, won't we.