Miller, I wonder if your large hook G grade that has the slot in the rib extension staked to keep the extractor in place might have been something done by either a gunsmith or a previous owner? Now I have to remember to look at my other guns to see which version they have.
I briefly thought about doing some kind of alteration on one of mine after I briefly lost it under my work bench. But I'm pretty much against doing anything to alter originality. Besides, as Dr. P points out, the guns I have that don't have anything to retain the extractor can only have it come completely out when the barrels are removed.
I still find it kind of cool to think that even the most advanced collector doesn't know everything there is to know about these guns.