It was unfortunate you forgot to tighten the wheel bolts once you finished the mounts. An oversight that could have been far worst given that you drove the car with loose bolts!! But it was good you found what the problem was a nothing serious happened. Metal parts can be replaced!!.
The original wheel bolts PN 1264000070 are non longer available from MB due to a tendency of the bolt to shear off. It was replaced by PN 1264010670 or 1084010070, shorter in terms of overall length but the same 40mm from the flange (which seems to be the ones you obtained from MB). However, Febi Bilsten and Meyle they still manufacture the long bolt but strengthened by 1mm at the head stem, and they are
available on Ebay.
The used hub on ebay at $199 is inordinately expensive for a 25 years old hub when a
new one would cost you just $41more!. It would be good if you replace the front bearings on both sides at the same time. When you start a project on these cars you never know when to stop!!.