I don't think the seller's trying to pull a fast one. I think they got the board with "Model M" already obscured, and maybe they did an image search, saw some F's, and figured this was one too.
The only thing that bothers me is the possibility of someone looking for an F who doesn't know that much about them—just that they're great, rare and highly desirable—and who buys this thinking it's one.
Maybe I'll just drop the seller a quick, friendly note pointing out the oversight, and see what happens. Cheers, A.