The $10,000 is serialised also.
That rack of chips are still in the MGM cage. I have seen them. I have even bought $5's and $25's up to quite recently, no problem. No MGM chip has ever been obsoleted. So no way any would have ever got out.
The $50k was turned down by gaming. $25k was the highest live chip in that series.

Ive seen a number of other colors on these denoms also, up to $100k. So I don't believe any of these designs matched the live chips exactly. Either samples or prototypes. For high denoms like this that won't make any difference to the bidding anyway.

If Ralph sees this I'm sure he will comment also.