Best left to a gunsmith
Go here: http://www.marstar.ca/AssemblyColt25AP.htm
Yes.
You can get a letter from Colt. It will cost from 75 on up depeding on specifics. Check their web site.
Colt.
made about 1920
Proofhouse.com has Colt sn data.
about 1921
about 1921
Nice small semi-auto that is collectable.
Proofhouse.com has Colt sn data.
@1936
@ 1912