made 1976
Proofhouse.com
You will have to call Colt.
made about 1972
You will have to call Colt. Published sn data does not show any Diamondback with a sn starting with a P
Post 78
1970
Proofhouse.com has Colt sn tables. You can also call Colt and they will tell you.
made about 1977
Around 1968.
are you sure the '0' is not a 'D' ????? in the serial number
1957