What scope for a 1980's weihrauch HW35?

[Rats Down .22]

Thank you all for the great and in depth information that I have received from you all, it has all been a great help to me.

I have decided to keep an eye out for a small quality scope from the eighties to keep the rifle looking as original as possible.

I do have some other questions though please, if anyone has the answers:

The Hw35 that I have has a barrel length of just over 16 and a half inches, does this mean it is a k version or has it just been shortened by a previous owner?
The stamped barrel just says Hw35.

It has good power (not chronographed) but seems very loud when firing. If I were to have it tuned would it quieten it down?
The previous owner stated that he had recently changed the spring and synthetic seal but that is all I know.

Thanks as always.

[Halimede]

A few more thoughts.
If your barrel was shortened, wouldn't it lose the foresight dovetail at the muzzle? My .177 HW35E (2018) has a barrel that is about 18 1/2" long and I wouldn't say that it was unduly loud. I put my serial number into Weihrauch's number calculator and although it found my gun it only gave me the year of manufacture, no build details. Try Hull Cartridge? AA once told me all about my TX200 when I gave them the serial number.
I find that scopes are more adaptable than diopters in that diopters are really only much use for target shooting. If you have (or have access to) a variable power scope, try mounting it and playing with the magnification to get an idea of what sort of scope you might want. I would say that there is limited point in going for say, a vintage two times and finding that you can't see the pellet strike. I think that diopters look the part but I certainly wouldn't hunt with one.