Don't know value, but Colt national match .45 with that serial number was made in 1969.
Don't know the value, but it was made in 1st year of production, 1957.
The Colt Gold Cup NM .45 with serial number 15051 NM was made in 1965
Your Colt gold cup national match .45 was made in 1969.
if in shooting condition I'd offer $500
The Colt Gold Cup National Match .45 with serial # 5219NMwas produced in 1959. made about 1959
Colt gold cup national match .45 with that serial number was manufactured in 1970.
The age and value of a colt .45 peacemaker serial 180356 are about 1900
About 1969 with that serial number for a Colt goldcup national match .45
made by Colt in 1945
made in 1916 by Colt. Your Colt has a Springfield slide, which is not unusual.
I believe in 1957 Colt ran a batch of 45 pistols with the prefix of 'NM' So, your pistol could be around 1957/58