i think your camera was modified ...
the handle pops up, and the hood is attached to it
the same way it attaches to other graflex slrs ( i use a series D,
and have had and used b's ) there are 2 clips that slide up /down as the hood extends
and the base of the hood attaches under clips by the ground glass.
the glass can be removed ( i didn't do it ) mine has a few screws and clip
that hold the glass in place.

i never modified mine but use 122 size spools i roll with paper, or a 5x7 sheet of paper right across
the film gate, it works great

good luck with your rebuild, its a great camera !