As pointed out above, call Colt defense at their 800 number and give them the serial number.
They will give you the born on date for FREE.
Free call free service. Can't beat it.
CUSTOMER SERVICE
Colt Defense LLC
P.O. Box 118
Hartford, CT, 06141
U.S.A.
Tel: 1-800-241-2485
Jeff (GUNKWAZY)