There are three variants in the W123's alone; none of which cross to W115 according to EPC.

A person would have to either brilliant or a complete fool to order a new switch from MB at a cost of $200-$300 and not follow the cross-referencing to VIN.

Now the realm of the recyclers is an entirely different matter. That is a cult-like group who learn by trial and observation about functional design differences and convey these details to their fellow cultists. Presently I find myself in this group and thankful for today's results.