I'm not familiar with it's use. Can you comment a bit on what the advantages are supposed to be for using olive oil as a wood cleaner?

My thoughts might be that it can penetrate into the wood like regular oil based finishes might. Once it's there, is that a good thing, any unintended odors, residues or reactions.

Mostly, I'd wonder about the collector's expectations. Maybe, you've seen what some of his other guns look like. Good luck with it.