There's no proof that those flashes were prototypes as-brought-to-said-meeting.
From the original prop blog:
View attachment 1471729
These photos also posted on the OPB from the Rinzler book are dated as
circa January 14th - January 25th 1976
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(You catch a glimpse of the grenade in the bottom left of the 4th pic, so I added the Grenade/Balance Pipe thing here too.)
Based on these dates, those photos are most likely the 'prototypes.' And according to Roger Christian, all of Stears' and the SP.FX. team saber hilts were the ones that looked like flashlights. (Which would mean that Christian's provisions to this meeting where the grenade and balance pipe assembly thing?)
So as of January 19th, 1976, there is no indication that the Graflex or MPP had been selected. (And oddly, the SPFX hilts were being developed concurrently before hero hilts were picked) And no other production memos I've come across indicate a date when they were picked... This one is interesting though:
So sometime between January 19th and February 5th 1976, the Graflex and MPP hilts were selected.
As for the flashes being legit ANH
production-purchased or "
from the collection of John Stears" ..it depends how optimistic you are.