That's weird qtan is a legit vendor. But I don't see anyway you could consider those thick. Maybe they are a bit thicker than the ones he used to sell?
Looking at the picture again nah those are totally thin.

I think they're
maybe thicker than Ducky's thin (or identical, difficult to tell), but thinner than Vortex's thick. I agree it definitely is not thick though.
I'm not sure if I misunderstood what "PBT Plus Thick" means, or if he's marked them up with an incorrect description.
Another shot, next to a quarter:

It's better than my ABS, so I guess I'll use these and wait a bit to see if I can get one of Ivan's blank sets (I prefer blank black over side-blue anyway).