According to EPC, that car has two variations: 004 545 3224 & 004 545 7524.

Neither of these used in my '73 220 and the W123 300D & 300TD use yet other variants that are different.

I don't dispute your success with the part, but this in one area where EPC is not very helpful. Indeed, if the bag or box was opened on these things and became separated from the part, you would pretty much be on your own to figure out what vehicle that switch was supposed to work with. I'm pretty sure that's how the new one I found today got into that box and had probably been there for at least 15 years or more.

Another interesting note on the matter of "pins" is that all of the signal switches I saw in Rudi's box had that same 14-pin connector.

Another minor electrical difference I have noted in the new switch I hybridized this morning is that with my old one I could flash the brights even with the ignition off. With the new one, the ignition must be ON.