The Colt Gold Cup "FN" serial number sequence started in 1983 and began with number FN01000.
1984 started at FN03653.
The last number publicly available was 1985, which started at FN11680.
If yous is higher, call Colt during business hours and they'll give you a production date over the phone.
They won't give out any other info unless you buy an Archive letter.