Serial number
Your colt 1911a1 was made by colt in 1945.
Model 1911a1
The ithaca made 1911A1 was produced in 1943.The serial number range was 856,405-916404.there was a total production for the war effort of 60,000 handguns.Your serial number falls within that range of numbers.
serial numbers for the 1911A1 government issue only go up to 2693613
That is not a serial no of a Remington 1911A1 they stopped in 1945 with 2465139.
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.
Made in 1942
In 1918
1945
About 1943.
It was manufactured in 1944.