proofhouse.com
Try Proofhouse.com
Best bet is to take it to a gun shop
Blue Book of Gun Values.
Find a book or website that has sn data for it and look it up
You will need to find a copy of the SCSW
Proofhouse.com has sn tables you can look it up on.
Colt factory: 1 800 962 2658............
sorry- no public database, and the company is closed.
No published sn data.
If you are looking for the serial number and can't find one, then there most likely is not one. For a time Benjamin did not put serial numbers on their pistols. I also own a Benjamin that has no serial number and had to do some research to find this fact out. Reference: "Blue book of airguns"
You will have to call Colt since you did not provid the serial number.