Has a big hole in the center... and looks like a felt-tipped ink marker made the "F" on both sides.

I'm going to assume the "F" represents the name of a club/group where the chips were used after being cancelled... Just my opinion since the example I've seen shows the "F" moved away from the center hole and not in the field where the "F" was drilled into (strictly my opinion from what I see on David's chip... perhaps other examples are different; I do not know, and that's why I'm asking).

John