Try proofhouse.com, if sn not listed, you will have to call Colt
No way to answer without a serial number.
100-670 usd
What do you want to know?
Without more of a description the best estimate is 500-1000
SN info on Colt's after 1978 is best acquired by calling Colt, unless you want to spen @$100 to get a Colt letter.
The best I can do is say that your colt Combat commander series 80 was made from 1983-1996.
10-800 usd
No such Model in the Colt line.
How can I find out what year Colt Combat Commander Mark 4 Series 80 was made?
The AR15 series
You will have to call Colt to find out.
100-1000 usd