Hugo,Your pistol is worth $1500 and up,The magazines alone are fetching upwards of $150.The gun is scarce,not too many built(Between 5 to 10 thousand).Keep it,it can only increase in value.There was about 7000 made from 1962 onwards,Then the rest in the 70s.Yours having 4 digit serial (Not knowing what the number is) puts it in mid production.And the magazine takes 5 rounds only.The normal stamping with Colts address should be on the slide and not on the frame.One other thing,the numbers should be first then the letters for the serial.

Ken