They're the curved blades, I'll take a stab at it when I get a chance.
Well I don't envy the next poor bastard that has to do this. I got the blades installed after a *lot* of tedious work, but then they didn't feel right.
There's two ways the blades can be mounted, one end has a pin more in the center of the blade, the other end has it mounted toward the outside of the blade...difficult to explain.
Since I didn't take a picture of the blades when they were out, I disassembled the lens again once I figured out the correct orientation for the benefit of people in the future. Here it is for your viewing pleasure (this is what it's supposed to look like, once the blades are correctly installed):
It's actually a very simple lens to work on and, once you know the correct orientation for the blades, the blades fall into place very nicely (unlike when they're flipped the wrong way).
I have triumphed over the Summitar!