Yuck! Not what I wanted to hear, as I'm planning to doing both W124 chassis soon.
If the stud was welded in, I suppose you are going to have to weld in the replacement, too, unless it is just like a carraige bolt. Not a pleasant prospect, actually.
Sorry I can't help!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!