I just checked my chips.
The 4th Anniv is 50MM with no H&C.

The $100 and $500 poker buy-in chips are 48MM with the inverted H&C.
Players do not play with them. They are won in satellites and used to buy-in tournaments.
I doubt they will be used again as a few did not come back in during the last tournament.
No, they are not available.