If you're referring to the Operation Retrieve document in STVI, the "Marines" referenced their were a fanon addition, the original chart came to light recently and it had different wording.
There was still Colonel West.

Yes, I know he wore the same uniform as all the rest of the Starfleet naval officers in that scene, but I don't care. It's the most logical explanation I can see. Starfleet is a navy; navies don't have colonels; the character was NAMED after a Marine (Oliver North); so most likely, West is a Marine. Problem solved.
