You could 3D print a copy, polish the surface and fix all imperfections to make it look picture perfect. With the right kind of paint job it can be made to look virtually identical to the real thing. That way, you could free up this camera for taking pictures without having to worry about its appearance. Or if you prefer something closer to the real thing, CNC machine a copy from a block of aluminium.
Alternatively, you could modify the lighting in your display case so that the blemishes don't stand out, or simply tilt/turn the camera in such an angle that they're facing a wall (assuming it's not a 360 degree walkaround exhibit). Assuming that from all other angles the camera looks pristine. If someone wants to take it from its display case, point out the lock on the case which is there for a reason, and also emphasize the risk of finger grease or corrosive traces in human breath causing corrosion over the centuries to come.
In all seriousness; isn't there a Leica museum in Wetzlar that carries the burden for all of us to maintain a collection of pristine Leicas of various models, so the rest of us can use our cameras, worrying about what we use them for instead of how they look?
I apologize for not understanding the first thing about the hobby of camera collection. It's a gene I'm afraid I was born without.