You've got a '50s Gillette Tech there. Those made in Britain did not get date codes, so you get the decade and that's about it. Nice one, though!
Gillette Old Types are an open comb. Gillette New Types are also open comb - these comb in short and long versions.
See: https://www.mr-razor.com/Rasierer/Old Type/Old Type.htm & https://www.mr-razor.com/Rasierer/The NEW/The NEW.htm
Nope, that's the New.
All the OLD and New Improved razors came with just their standard open comb. The early ABC Canadian made razors had teeth that were made slightly different but that was peculiar to that model only. The New razors that had a separate head could be had with a long comb, short comb, or long comb Deluxe, which had a heavy baseplate with a flat bottom. The Deluxe also came in two slightly different versions, one with 15mm between the teeth on the bottom, and one with 17mm between the teeth, the top looked the same on both, just the angle of the cut between the teeth was different. The long comb and short comb had completely different baseplates, not just different length teeth.