In the past I have drilled out the screws and replaced the rubber catch inserts in my 123, it was a PIA but was happy with the results.
I picked up a Euro 1st Gen 126 (has the aluminum striker housing not the bent steel ones) and the plastic catch inserts were crumbling, had to slam the door to close it.
I decided to try a different approach to the problem and made the two parts of the catch insert that are needed in a way that they can be inserted into the catch housing without having to touch the 4 mounting screws.
In the process i found that the aluminum housing is thicker then the stamped steel ones (of course after i had made the first one lol), and I found some details that affect how the door opens.
Only tools that are needed are a small screw driver or pic to remove all of the original insert, and a pop rivet gun. Attached are pictures of a striker insert and the new parts, the striker as it was, and after installing the new parts.