I suspect original scopes are pretty pricy.

An older Kahles/Swaro/etc in 4x32 or similar in high mounts might be nice, similar to the various WW2 originals (Henstoldt, Kahles etc), and not exorbitant if you shop around - 200 or less (and would have 100% resale value if/when you got bored). Or rig up a ZF41 style set-up with a pistol scope (or, better, a Leupold Scout scope).

Me, I think I'd keep the irons. Ideally I'd replace the rear sight with a range-graduated arrangement marked from 100 to some silly distance like 1200m.