"What I can see" with my tired 57 years old eyes is not much on the bad small screen of my old obsolete PC, so my testimonial is obviously to take with a grain of salt
That said:
-I'll inspect the mounting legs of my own remaining vintage 59's (they are currently all mounted in various guitars) but the threaded baseplate and other parts in the pics still look familiar to me ;
-the color of the mag is not really meaningful with vintage SH1's IMHO/IME. All of mine include RC A5 mags whose main tint is a dark blueish grey.
Now, there is an extremely simple way to check if the mag is ceramic or not: take a multimeter, put one of its probes on one side of the magnet and the other probe on the other side (without touching anything else). If the DMM gives no resistance reading (if it shows an infinite resistance), it's a ceramic mag.If it gives a DCR reading, it's not ceramic.
Last but not least, the uneven look of the baseplate with its "tides" made me think to a kind of flash wax potting done after purchase (and possibly on the baseplate alone, in order to fasten the bottom of the mag on it). It would be understandable knowing how some early unpotted SH1's tended to squeal and it might explain some missing label(s) / paper wrap.
Each of these statements is pure conjecture. Any
serious diagnosis would presuppose to have the pickup in hand IMHO.
Footnotes:
-one of my vintage SH1's had a RC mag GLUED on its baseplate. My friend luthier had kept it on a shelf during 3 to 4 decades and didn't remember to have done such a thing. I'm still wondering if this unusual operation had been done in the factory or not... strange things happened back in the days so I wouldn't necessarily expect consistency from old products.
)
-I've dissected/repaired some vintage SH1's and wouldn't recommend to open any of them if it works: IME, they are frail and prone to develop intermittent contacts if their bobbins are handled repetitively. :-/
FWIW : conjectures and subjective testimonial + feelings, like any post in such cases...
