So it isn't the servo, which leaves the radio. Whether or not it was or wasn't a quality product in days gone by, it sounds like it's broke now. Some wetting of the dry joint, or joints seeing as it has had time for the solder to age, will add only a little to its weight, and therefore quality, and might rejuvenate it and leave it running like a new one. Apart from the change in signal standards in the intervening years regarding channel separation.
It is always possible to add a little lead to the underside of a modern radio if it is felt that more weight will improve quality. I have never come across a receiver with a meter fitted, nor have I ever seen one with anything other than a wire aerial, even the self supporting aerial on some boats is a plated wire.
On the subject of polished waste matter, I think that Mythbusters found that if you dehydrated it first, a good lasting polish was possible. Whether anybody would appreciate it as a retirement memento is another question. There is also a high probability that the engraver would decline any further jobs.
