...and though I've never noticed one, I would assume it is oval.

I also almost gave up trying to find where they were used and have not discounted them not being from a casino (colors) with a wheel; where the 5000 was stock reverse inventory since it wasn't uncommon for a personal set to have a high-denomination, wheel-stacked plaque. Salesmanship, I guess.. and even though casino is my first choice; you never know..