I don't remember last time. They've been in there for 3 years through 3 salty winters.

This time they're coated with anti-seize compound (lithium grease + aluminum powder mix).

Even if I stripped the holes, it just means drilling and retapping, not a huge deal, I'd just be into nonstandard screws then (M6 instead of M5). Not a big enough change to affect the frame strength or anything at all.