I think you mean colt 1911A1 which was the US military handgun from 1911 to about 1985.
Your colt 1911a1 was made by colt in 1945.
1943 by colt
made by colt in 1943
made by colt 1918
It was made in 1945 by Colt.
Proofhouse.com has Colt sn data.
Proofhouse.com has Colt sn data.
Your colt model 1911a1 was made in 1945,plus the serial number puts it in the range of the Remington rand numbers in my references.
your colt model 1911A1 was made by colt in 1944.
Proofhouse.com has Colt sn data.
1945