While it would be great to see some brand new replica's of the 375 or, my personal favorite K-27's 460 and post-wreck 455, it makes sense to preserve or restore currently exsisting locomotives first.
I do think that common sense should be used in restoration. For example, if one of the K-37's needs a completely new boiler to restore it, so be it. The railroads thought nothing of reboilering a locomotive if it made sense economically-look at the T-12's for example. Then a cosmetic restoration restoring the rest of the locomotive to a traditional K-37 style appearance could be done.
Here is my real point. If the dead 492 were locked away in storage where nobody could see it, and the entire boiler were completely replaced and the locomotive was restored to operation, would anyone be the wiser or object to having another K-37 in operation?