Okay, posting on behalf of a friend.
He's got a '69 350 with the rear hub that uses the two tin keepers with bendable tabs to hold the sprocket bolts in place and the big circlip keeping everything snug back there. Pretty straightforward stuff.
He has found a much cleaner rear wheel with a different hub setup. Circlip is still there but the sprocket is held on by four studs that slide into the hub almost like a rudimentary cush-drive. These studs appear to be pressed into the sprocket (haven't tried to bang 'em out yet).
Sorry no pictures, but does this sound like a later model 350 hub? 360? 350F? Riveted directly on to the sprocket is a factiry dorky sheet metal shield roughly the same diameter as the sprocket itself. Sound familiar to anyone?
Honda go sideways!