Not really, if a mechanic is dumb enough to use bolts that aren't "NAS or AN" where they are required, that bothers me, however, the use of car sheetmetal screws in a non structural place or the same component from a car just its not "FAA/PMA Approved" that's not really a big deal as far as I'm concerned. Look, I used to work in an aircraft parts store, it was a terrible job, but other than that, we'd say "go to napa" for some stuff a lot if you didn't want to pay $150 for something that should cost $20