I have been doing more research down a different trail. It looks like we started getting prepaired for WWII as early as 1939. We had 30 new Training Bases under CRASH construction in 1940 - 1941. (Pre Pearl Harbor) Most of these bases were considered Semi-Permanent (Life of buildings 5 thru 20 years) WWII Semi-Permanent bases has Special Services facilities, Churches, etc in the original base design plans. Not added at some later date as an after thought. Barracks buildings had latrines incorporated into the original designs for the first time. Troop Strength in 1939 was listed as 210,000 by the summer of 1941 we were ahead of projected numbers at 1.5 Million troops. (Again pre Pearl Harbor) I was reading about Fort Leonard Wood. It stated that a building was being completed every 45 minutes in 1941.
After Pearl Harbor we started construction on another 35 Training Bases in 1942.
The 30 Training Bases under construction in 1940 - 1941 would have had a requirement for Riot Guns for Guards and MP's. Special Services would have had a requirement for recreational shotguns for trap and skeet as well as hunting. Training Bases that did MP training would have had a requirement for Riot Guns for that school. The bases doing training for POW Camp Duty would have had a requirement for Riot Guns.
Their would have been a contract to purchase these shotguns with a delivery date in advance of the guns being needed. Troop Training was being done at some of the first bases under construction in 1941. So we had to have had delivery of shotguns during 1941 to arm the new bases.
The 3 EARLY WWII Model 12's we have located so far have a serial number spread of 520. Two are Full Choke 28" barrel guns and one 20" Riot gun. My gun has the lowest serial number of the 3 and has a 1940 barrel stamp, the other 2 have 1941 date stamps on the barrels. I believe all 3 have a 1941 Serial Number range.
With 3 Model 12's all marked with the same Military Stamps, and Inspector Markings, with a Serial Number Spread of 520, we have a contract purchase. With the serial numbers of all 3 being Pre Pearl Harbor it would likewise be reasonable to believe these guns were purchased to arm the new bases under construction in 1940 - 1941.
As far as I can find out 20,000 Model 12's were purchased in WWI and another 80,000 in WWII. My guess would be only a fraction of the 100,000 Model 12's are in civilian hands today. With an early contract for probably 1,000 guns or less. Finding 3 from the early contract so far is probably not bad. I am sure more exist.
A friend of mine went to work for Special Services in the 1970's. He told me that they sold off used shotguns from inventory in the mid 1970's just after he went to work. This could explain how the Full Choke ones came into civilian hands. After WWII ended, Aerial Gunnery Training would have been phased out. With no need for Full Choke Model 12's they very likely could have been transfered to Special Services. This could explain why Texwings has the bracket on the barrel for what was probably an aerial gunnery sight, along with Special Services Property stickers.
I have no doubt that we have located the 3 earliest WWII Model 12's known to exist at this time. Without the internet we would have never connected the dots on these 3. I believe more will surface as time passes.