"Atlantic Club" = a fantasy casino, meaning the chips will resemble casino chips but aren't from a real existing casino. "Atlantic Club" was one of
CPC's in-house "Fantasy Casino" options, sold as a stock set with standardized colors. This enabled people to buy chips right away, whereas a custom order would take many months to receive.
Atlantic Club would be the info in the center of the chip, while the chip's "Mold" is the ornamentation around the edge. The "A" mold has "A's" around its rim, whereas the HHR has horseheads. It's like getting a sports team jersey in the home colors vs away colors. Same info, but different visual design.
CPC whitelabels chips for "Key West Resort Casino" meaning this one buyer buys in bulk from
CPC and sells them himself, under his own created fantasy casino called "Key West Resort" which of course doesn't exist as a real casino. He has them priced very competitively, and I believe has ample stock if you wanted to buy a set today. They're on the "H" mold which I quite like, very classic and widely used across Vegas casinos back in the day (but no longer).
https://www.keywestresortcasino.com/casino-chip-info.html
I doubt
CPC will continue making Atlantic Club after they move, but I could be wrong. The new owner plans to do a design contest for the new "Stock set" to be offered, which will probably be a new "fantasy" casino name, a particular mold, and a standardized color progression across the denominations. I'd expect that's a long time from now however, so if you want some
CPC chips check the classifieds or consider Key West.