Hello,
I had a chat with some materials friends on coatings on CFRP.
The typical gel coats don't provide any particular resistance. The moulding and autoclaving process means that there are limited resins available for use. Usually a Vinyl Ester, which is what I guess is used on your watch.
There have been tests on sputtering Nitride coatings onto CFRP (a cousin to PVD). But due to the relative softness (RM 80 ish) of the underlying material (the resin/fibre matrix) it didn't show much improvement.
So my guess is, that thing will be stiff, but be careful of door frames!