I understand that the fix for the OM's is to simply clean out the old foam and reassemble the camera. Apparently they put the foam in to keep outside light from reaching the sensors near the viewfinder, but the consensus is that the top covers are light tight enough that the foam isn't necessary.

I just ordered a set of the nice OM tools from Beljan Mfg. I think I'll do my beater OM-2n myself, and if that goes well I'll do the others myself, too.