The first two are still more than 50% costlier than $50. It's not like we're talking about old but desirable multi-round pumps or O/Us, where repair and/or improvements often make sense. Not many people go out looking for old single-shot shotguns. Many of those shotguns were borderline (if not outright) crap when new. Many of them now are kaboom sticks waiting to happen, especially with modern loads. Many of the old, cheap side-by-sides are even worse.
Especially when you go back to the damascus barreled guns. while some were fantastic quality for their times, if you use modern smokeless ammo in those, and the steel might 'unravel'.