I pretty much agree with Lyonsarcade's assessment.
Get the thing ready for the use and abuse that it will take. If it's going out for home use (as most sales are), you can let some things slide since it' won't get as much use (in theory).
Although it is always good to ask exactly what was done by the seller.
I would never assume that a monitor has been recapped if a machine has been shopped. In many cases, the monitor may not have needed a re-cap. So why would a seller want to re-capp a monitor for no reason?
As for pins, it should be new rubbers, blown lights replaced, any worn/broken plastics or features replaced, Playfield brought up to spec, and any other adjustments made.