i was also looking at a 5512, but the dial was from a 5513(service dial) as was the caseback( supposed to be correct) so i chose as clean a 5513 as i could find.
i've done a bit of reading and the 64 5512 i was looking at was a chronometer which should have had a 4 line dial. i note yours is not chronometer certified. without reading all the stuff again, i'm remembering some 5512's were cosc and some werent. i'm assuming yours is one of those not certified.
i usually save everything i read to my favourites, but would you believe i cant find it so i cant check up on my memory.
if i could find a good 5512 4 line chronometer i may go for that as well although they are not as popular as the 2 line dialled 5513's or 5512 in your case.
i will desperately try to find the rolex history i read before so i get my facts straight, but congratulations.
best
Graham



