Replying to myself for anyone else looking in future:
http://optical.kowa-opt.co.jp/ts/e/concept/history.html
The model above is a TS-2 from the 1950's Kowa has moved to a bayonet fitting instead of screw thread, so will look for second hand (very old) eyepieces.
And yep, definitely scratched as I can feel them under my finger sadly.
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