Re: They ought to wear a mask!!!
I've never had the occasion yet to look at any Mercedes lamp sockets, but if it's just a round hole of maybe 1-3/4" (metric of course), any reasonably stocked auto parts store ought to have universal sockets that can be spliced into the existing wiring and snap into the hole.
Failing that, I'd just grab one off another car at a wrecking yard, with or without harness. I'd do the same with the mirror.