833 4spd repair advice
A story for you:
I purchased a '68 charger (440HP/RT) from a dealer about 100 miles away. The PO said it leaked tranny fluid, so make sure that problem was OK. Fluid was checked. It was fine. I drove it home.
I checked the fluid a week or so later having driven it regularly during that time, sure it was OK 'cuz there wasn't a drip on the garage floor. There was NOTHING in it! I drove it to a shop that found a hole in a poorly welded front bearing retainer. All of the gear oil had come out on my way home!
The trans survived just fine. Granted, a transmission with 20K miles on it is NOT 'just rebuilt'. Driving a 4000lb big block over four mountain passes and 100 miles isn't quite 'idling in neutral' for ten minutes, either.
Assembling a rebuild without lubrication is a possibility, but extremely unlikely. Having it NOT full of fluid is normal, too. That is the installer's choice of lube and responsibility.
Honestly, sending a car to a shop for a 'once over' for bolts and nuts is beyond my ability to comprehend. To each his own, but IMO, you should not own a vehicle NOT under factory warranty and maintenance; Certainly not old-iron Mopar stuff.
Learn yourself things. DON'T drive it without knowing the clutch adjustment is good and knowing yourself that the entire vehicle is lubed/fluided/checked for basic operation.
Good luck!