Won't post who the seller is as I've never purchased from before. This seller had quite a few Luxor $1 posted and I sent them a question in regards to if they knew what UV marks were on the chips.
Here is the response:

These came directly from the Luxor main cage. The Luxor never
put any markings on their chips. Some dealers were trying to
increase their sales and were marking the chips seen with
ultrviolet light. These marked chips appear original, but they are
not Luxor original. If you recall who marked your other chips,
contact them. They may have the rest of your collection, or send
them my original Luxor chip and ask them to mark them. I've
been playing there since they opened, about 14 years, they have
never marked their chips. I've heard this story so many times
before, it's a hoax.

I wouldn't think that you could "add" a UV mark and not have it wear off over time.
How would you respond to this hoax claim?