Don't have any extended RB stocks to show you but these extended RB-to-SB should at least give you an idea of scale.
Top (K) is a 617-4 extended, bottom (J) is a 60-4 extended:
Stocks are raw wood which explains the dullness, esp. the walnut (which actually has nice banding which I think will show well w/ the eventual handrubbed pure tung oil finish). Need a bit of sanding still for the fit I want.
K is a little deeper than the J as the handle is a little deeper. Other than that, hard to tell the difference. It's a handful.
I should add: I go the custom fit option, where Craig has possession of my guns. That's why they're scalloped on the right side as well-- I'm a lefty. Plus-- I prefer the look.