The Colt Gold Cup NM .45 with serial number 15051 NM was made in 1965
Proofhouse.com has Colt sn data.
1974
1983
Colt gold cup national match .45 with that serial number was produced in 1961.
where was the colt gold cup national match serial #70n51714 made
approximately 1974
1962
Goes beyond published data, you will have to call Colt
You will have to call Colt to find out.
Colt gold cup national match .45 with that serial number was produced in the first year of production, 1957.
You can find out at Proofhouse.com in the Colt tables.
Colt data at Proofhouse.com