What if the cotter pin remains the same as seen in above picture (so in fact only half a leg remains on the cotterpin the other half is cut off at the other end once being through the bearing ... get it?) and the booster
is screwed inside the graflex clamp stuck behind both tab holes ridges ... is there then an opening to get that one leg of the cotterpin wired through the first 'mistaken' eight hole and once out then pulled tight through the other eight hole and cut short? So that it's only purpose will become to hold the graflex clamp in place keeping it from spinning around a little on the booster bearing
Mind you an Obi-Wan ANH lightsaber with this booster + booster bearing configuration attached like so inside the graflex clamp, will hold the booster already fixated tightly onto the clamp . . . on its own
That's why initially no cotterpins would be needed, as James Kenobi has pointed out earlier, however during principle photography and dropping the lightsaber once again for say 'take 327' it could possibly have been heavily damaged and needed restoring after filming, just in case lateron some more pick-up shots with Alec Guinness and it's lightsaber-prop were needed for whatever scene necessary.
Keep us posted Kurtyboy,
-Chaim