KS,
If you don't have Diggory Hadoke's book "Vintage Guns: Collecting, Restoring and Shooting Classic Firearms", you may want to pick one up. He covers the 12/20 and other sidelock actions. The 12/20 was built to be a light gun (6 to 6 1/4 lb range) as it came out in the late 20s timeframe and was competing with other lightweight guns of the time (Churchill 25, 2" guns, etc.). It is not a bar action lock, but definitely looks like one except for the missing front pin. As you already probably know, every gun has to be individually evaluated.
Ken
