I just went to an outbuilding and had a look at a GEN 1 W126. None of the doors have any sign of welding or bolts or holes around that limit strap. Nothing but flat surface around that part. I wonder if yours had previous work?

The main direction of force is pulling on that part when opening., which is probably plated on the back side, so those welds would not be doing much. Why would they want to go to the trouble of spot welding in that location when they could have just tacked it from the back? Not much force pushing in when the door is closing. I'd like to hear others with GEN 1's weigh in on if their jambs show that same arrangement.