Find a book published on it or the manufacturer and see if it has sn data in it. Check the maker web sites to see if they have a sn look up function. Try Proofhouse.com
You find a published list of serial numbers for the maker.
You find a book with serial number information and look it up. You find a book with serial number information and look it up.
Look up the serial number.
Try Proofhouse.com
If data has been published, you look it up.
You will need to call Colt
If sn data has been published, you can look it up.
You find a web site or book(s) with sn data for the weapon you have and look it up.
IF YOU CAN REMOVE THE HANDLE THE SERIAL NUMBER SHOULD BE THERE. YOU CAN TAKE THE GUN TO YOUR LOCAL POLICE DEPARTMENT AND HAVE THE GUN REGISTERED OR SEE IF THEY HAVE A PROGRAM WERE THEY BUY THE GUN.
try: proofhouse.com/colt/index.html
NUMRICH GUN PARTS SELLS DRAWINGS , BUT YOU HAVE TO HAVE THE MAKER TO START LOOKING
that depends of gun maker. colt's, springfield, S&W and similar gun makers have books on gun dates. who made your gun will depend on a serial listing being available......