I pulled my front calipers on my 1992 300ce to replace my discs.
Put the old bolts back in, with some good loctite.
All is well.
I would think its ok to use the original bolts as long as you clean them and use some loctite.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.