Proofhouse.com has sn data. If not there, call Colt.
Your colt 1911a1 was made by colt in 1945.
1943 by colt
Serial number
made by colt 1918
made by colt in 1943
It was made in 1945 by Colt.
1945
In 1918
About 1943.
Proofhouse.com has Colt sn data.
made about 1917
It was manufactured in 1944.