If it is on a stand, I would pull the pan now, before priming the engine, flip the engine over and make sure as much junk as possible is out.
I woudl even consider pulling the crank out just to make sure there are no big chunks that could screw up the engine.
Is this a fresh rebuild, or just a oil pan change.
Better to spend the tiem now, that screw up the engine boyond repair later.
Jason