OMG! Finally a picture of an M that looks like mine! Yes, this is about the same level of grime each of my Ms started with. And I just put them to use. Over time, my fingers have cleaned off the grime so most of the keycaps are normal again, but you can tell I don't use certain keys very often.
Very nice deal for whoever got that one--should be in almost perfect working condition if the barrel plate doesn't have any cracks.
