I'm doing some research on the driveshaft couplers, and it looks like there was a problem with the factory bolts? Was it that the bolts are strong enough or weren't correctly torqued from the factory?

I've also found four GM numbers.
92246146 and 92228337 seem to be the same size.
92249108 and 92228328 seem to be the same size, but are slightly bigger than the other two. What gives?