Do you know about how much something like that would sell for if I decided it wasn't for me? I like the idea of owning it but not losing my shirt if it does not work.
Welcome to LTG! A mid 50's M-75 Aristocrat in excellent condition can be valued at around $5,000-5,500. Now you said she might need a refret so take the amount required away and you are still at $4,000-4,500. Obviously condition is everything and all needs to be original and the case as well. The tuners in your picture certainly look very good.
I can't read the first number of the serial number clearly if she is a 33xx she is from 1956, if 53xx she would be from 1957. I have a 1956 one myself.
Regarding those marks I would agree with Brown-Recluse, that looks like the nitrocellulose lacquer melted from some plastic coil guitar cord which was stuffend in the case under the headstock.
EDIT: I just looked at my one, that's the 3 and the 5, so yours might be 33xx, means 1956.
Ralf