I have a pre-ban Colt Sporter Target with a mismatched serial #. The early 90's sporter serial #s are prefixed with the model type. ST for the Target, MH for the Match HBAR, NL for the 9mm lightweight, SL for the Sporter Lightweight, and CH for the Comp HBAR. My rifle is marked "Sporter Target" but it has an MH prefixed serial #. How rare is this mix up from the factory and does it add any value to the rifle?