Instead of using thread protrusion as an indicator of bolts being intact, I’d recommend using a bright colored paint marker to mark the heads. A line from the head past the seating surface will give you a better visual. If the line is separated, you know your bolts have loosened. Use a paint marker that is cleaned off with solvent like brake or carb cleaner so you don’t have a bunch of different “permanent” marks that negate the benefit of marking!

In my experience the marking is necessary with the 6 bolt M8 joints much more than the joints with M10. I had M8 joints on my ‘79 SC and I was surprised that I occasionally didn’t find a few loose ones. In all the checking I did on my ‘87 Carrera’s M10 joints for pre-track tech inspection, I never found them loose. Whereas the M8 bolts clearly appear to be the sketchy ones for folks here on the forum.