That's an interesting 2-sided / different casino name chip you have there.
There were actual 50c Silver Slipper and 50c Jolly Trolley hot-stamped chips made, using the "cream" colored Bud Jones dice-and-cards mold.

They are shown on the MoGH ChipGuide, but for convenience, the links are:
https://chipguide.themogh.org/cg_chip_search.php?ccg=065697
and
https://chipguide.themogh.org/cg_chip_search.php?ccg=061947

The issue dates for the 2 "normal" chips are 1960's for Silver Slipper and 1977 for Jolly Trolley, per info on ChipGuide.

Also note that there's a Borland "remake" of the Silver Slipper 50c chip, shown on the ChipGuide at:
https://chipguide.themogh.org/cg_chip_search.php?ccg=182234

Considering all the info above, here's 2 theories, but both have holes in them.
1. The chip stampers at Bud Jones stamped one side (the 1960's Silver Slipper side) as a test piece, when they were adjusting the temperature and pressure on the gold foil stamping machine. Your piece looks good, but let's say it was what we call a test piece/floor-sweeping that went in a test-piece/reject box, with the other side blank. Then in 1977, when making the Jolly Trolley chips, this one-sided piece was retrieved and the other side was stamped with the Jolly Trolley die, thus making your 2-sided chip. BUT, I find it unlikely that a floor-sweeping chip like this would be stamped in this way with a decade between the 2 tests ... AND this error/maverick/mule chip made it out of the Bud Jones factory and into the market for you to acquire. (I'm discounting that a Bud Jones employee did this intentionally, with no record of such shenanigans in the BJ factory, though anything's possible.)

2. Since we know that Borland did do "remakes" of the Silver Slipper 50c chip, he could have done a 2-sided "mule" like the one you show. EXCEPT, we have no record of him having access to the Jolly Trolley 50c hot-stamp die. Is it possible Borland DID have access to that die, and made this error chip intentionally? Yes, possible, but no record that he had access to it.

My conclusion -- I don't know! It's a head-scratcher, but a very interesting error/mule chip, given all of the above.

It's an interesting find. If you care to reveal ... how did it come into your possession? Just a lucky error find on eBay or from another collector or dealer? Or another interesting story?

Sorry for the wordy response.