Hi Les – no, it’s odd because the material is only deposited on the inside of the dial cover, nowhere else. And yes, it could be an indication of a malfunction although there is no indication of overheating anywhere on either the top or bottom of the chassis.
I was suspicious that it could be paint from the metal dial that had evaporated onto the dial cover, because the dial background has been repainted and a new scale applied. But again, there is no indication that the dial has gotten hot, and there was no material deposited on the dial pointer. And why would anyone repair the dial if they couldn’t see it through the dial cover?
Gary