Dave, for a COLLECTOR originality and condition is paramount and in that market any deviation will adversely affect both desirability and price.
However, in the real world of practical guitar playing a well-repaired crack is quite acceptable and a not-infrequent occurence on a guitar which may have experienced extremes of dryness and humidity.
Tuners frequently wear out and you can look on them as consumables-like car tires.
I prefer to see an original finish irrespective of condition and I would also prefer an original bridge.

Structurally, the most crucial thing to look for is the neck to body angle; elderly guitars frequently need a neck reset-although if the guitar was played regularly by a knowlegeable musician, a reset may have already been done.
If not you will have to factor in that cost in order to have the guitar play to an acceptable standard-as far as the action is concerned.

Might I suggest you buy Vintage Guitar magazine; it's crammed with ads from vintage dealers and will give you a good idea of prices and availability.
Feel free to ask if I can help in any way; Gibson guitars are a bit of a passion of mine!