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.