For several years now I have been using a vintage Kowa Prominar junior spotting scope with a fixed straight 20X eyepiece which will show 22 bullet holes at 100 metres but not 200 metres or sometimes when when the light is right in the white with a bit of a struggle and guess work.
Before Christmas I bought for a song online a vintage Kowa and a really nice stand which I bid on to replace the stand I was using.
Came with two eyepieces which I didn't realise came with it as only a blurred photo showing a 20X eyepiece and no mention of another eyepiece.
The small smooth and light focus knob is under the scope.
With the eyepiece shown I can see 22 bullet holes at 200 metres.
Nothing on the body of the scope except Kowa to show what model it might be.
So I wonder what power the eyepiece shown actually is.
Must say the angled scope is so much easier to use.

That really is a vintage Kowa. Am guessing the folks at Kowa USA would be happy to answer your question and would enjoy pic's of your scope. They've always answered my questions over the years.

That scope was also marketed by Bushnell as a Spacemaster.. I have used one for years. I use a Kowa TSN-1 on the range now.

Mine is earlier and doesn't have any tag, or Prominar name plate. And no signs of it ever having a plate anywhere either. I think mine's a pretty old guy.