The fogging that you see is rather common in older instruments which is generally related to worn seals that allow moisture inside the unit.
Usually, the best fix is to send them out for overhaul and refacing. When you get them back, they look and function like new.
The vacuum gauge......who knows?
I think I still have a recently removed vacuum gauge (with a face) that I'll be glad to send you if you want it. I have no need for it any longer if you can use it.
