A833 buying tips?

I guess you all are pulling the side cover when buying a 4 speed? What if I'm the seller and I say " no" to opening the side cover...?

I'd only take it if everything felt smooth, no other signs of issues, and I'd still pull the speedo sender to ensure it wasn't full of water at some point.
I'd also only make the deal if it was cheap, knowing that it probably needs bearings/synchros at a minimum.
If a seller wants top dollar, they'll show the buyer whatever the buyer wants to see.