I was thinking same thing, and unfortunately they definitely appear to be so ?.
Luckily those that live in 1-plate states won’t need to worry about this, but drilling into a bumper like that is a travesty and I’d personally never do it regardless of state regs; 2-plates are totally unnecessary to begin with IMO
Id imagine there’ll be aftermarket relocation kits soon enough that mount to the tow hook, which still isn’t ideal aesthetically but better than drilling.