Silver -UNmodified- Kobold flash unit (D-ring added), shoven into a Graflex top (no glass-eye, no red button), partially painted.
A couple of these builds surfaced already, yes
We now know they did this for the scene where luke lost his hand, jamming a Kobold into a graflex.
This specific stunt with the black top has only been seen in that shot I think, it might have been a back-up stunt, used to cast the stunt they threw at Luke in ROTJ or a promo piece.