Picking my brain won't take very long, I assure you -
Hopefully I can relate what I've learned after dealing with these motors since buying my Pace Car in '94. Only options at that time were used units, no reproduction of any valve and coils at all. I searched high and low for pieces and parts, even attempted to have the valve reproduced by an injection molder, which proved too costly for me to undertake (mold was $20K +). I still have a GM produced print of the valve, but the current reproductions are really good and not very expensive as things go. Features and material colors are pretty darn close -
I use the original bolts for the motor housing - they were oxide finish, and painted with the housing, not zinc finished that I've ever seen ( I bead blast mine and paint with the motor). Crown of the original bolt is about half the height of the ones in your pic. Coils were batch dated; Heartbeat's dates are good, although the fonts are incorrect (if the pic I've included is clear enough, the October date on my coil is an original GM ink stamp). There is a pick of one of the 2 NOS GM coils I have to show what the manufacturer stamped on the coil end frame - they were dated as well. I think the repops have caught up with that.
The best way to tell if the gearcase has been rebuilt is to look at the "rivets" holding the case halves together - they have 4 tabs bent back to lock the halves together, very difficult to close them up and separate the case without damaging the tabs. If the field coils and armature of the motor are reused, the only other things to consider are the brushes as a wear part. You gotta consider these are tough little motors, and even in rainy climates were not used every time the car was driven - most used motors still have a good service life left.
As I said before, I think your unit looks good, just a couple of cosmetic changes and I think you'll be all set. Hope I haven't caused you any duress - I apologize if that's the case.
Regards,
Steve