Since the overstamps on the Harolds Club roulettes are from rubber-stamps, I'm guessing the marking were applied after the chips left Harolds. There were thousands of these chips made available to dealers and many undoubtedly ended up in home-play. It would be cheap and easy to get numeral rubber stamps and make 5, 25, and 100 chips for your poker games.

It's always possible that they were stamped for use in a tournament at Harolds but I have no evidence of that.

It's unlikely that the two sets of 6 table numbers were used alternatively to prevent ringing-in, as the colors are the same. It's very difficult to detect different hotstamps on a stack of chips on a table. If fraud prevention were the intent, they would have been made in different colors or given edge markings in my opinion.

Although these chips are some of the most common old roulettes out there, it's still very hard to put together a complete set. I've been trying for several years. There must be crates of some of the table numbers or colors still sitting in a warehouse (or dump) somewhere. I believe JohnB said there were large quantities in Florida at one time. I've seen eBay listings from the midwest as well, but not for a year or so.

I've given my input to TCR authors on relative values based on what I've been able to get and what I see at shows. Hopefully TCR10 will have some further info on which tables/colors are harder to get... and which are impossible.