GI 1911a1 series .45acp pistols....
I'm not a firearms expert but I did serve in the US armed forces & used a old Remington Rand model 1911a1 for 12mo.
I read somewhere; I think The Living With the 1911 from Boatmanbooks.com that the US armed forces & DoD/War Dept ended production of new 1911a1 .45acp pistols around 1946 or 1947. For decades, the US military just used spare parts & service work to maintain the 1,000s of .45acp sidearms produced during all of WW2.
Not until the new M9 9mmNATO in 1985 came out, did the military pistols change.
Every 2nd matters.