Different keycaps in CoolerMaster Masterkeys series?

I have a Coolermaster masterkeys in both M and L (white leds), and I noticed that the keycaps are different between the two. The L has smooth keycaps which attracts oils, whereas the M keycaps has a somewhat rougher (around the edges) keycaps and does not attract oil (matte). Even though both are cherry red switches, the L keycaps are clickier and louder when bottoming out. The thickness of the keycaps in both keyboards are the same. I tried the water density test, and the L floats 100% of the time but the M keycaps float if I don't push it down all the way.

Is Cooler Master using some pseudo-PBT caps? Or are they both different quality ABS? I don't want to destroy my caps in acetone or boiling water to find out; hopefully someone has experience in this.