You can date this Superspeed to within a few years ...., The Superspeed came out in 1947, but for the first four years they were uncoded since Gillette didn't start adding date codes until 1951.
The very first Superspeeds were also un-notched - Gillette notched the razor in early 1948, thus making it possible to hook a blade over the centre bar using their then new plastic (cream coloured initially) blade dispenser, and so making loading of the razor even safer.
So this razor therefore dates somewhere between 1948 & 1950.
I've also bought razors from this seller in the past and would thoroughly recommend him as he offers a good service & an honest description. He posted to the UK when I dealt with him, maybe he still will if you ask him beforehand.