1B,
Let me clarify: In the first years, the .308 Winchester was made in up to 10 different configurations! The most common was the 22" A barrel, beavertail forearm and no sights, what would be called an AB today. This was the 2nd in numbers of all non-prefix No.1's produced, following the 1B in .22-250.
All the other configurations of the .308 would be considered rare to extremely rare. The 22" A weight barrel is also found with Alex Henry forearm, and no sights; more of these are known than the "true" 1A; that is, the same with sights. Only a handful of these are known. John Amber test fired one, serial #110, in the 1968 Edition of Gun Digest. The rifle is pictured with the front sight hood, which it still has!
I guess to really muddy the waters, the 10 configurations of the non-prefix No.1 were the AB, ABS, AH, AHS, BB, BBS, BBB,BH, BHS, and BHB. Also, one example of a non-prefix 1V in .308 has been recently auctioned off by the Factory.
If you want to know more, go here:
http://www.classicsportingarms.com/?page_id=10Just recently was the 1A in .308 was added back to the catalog. I do not believe it will last long. Therefore is my point, those that want one better get one now, as I do not expect this caliber/configuration to come around again!
Edited to address your point about your .308 1B; it was back in the catalog a couple of years ago, maybe also in stainless. Now gone! If you have had yours any length of time, it is likely a non-prefix!