The purpose of this bolt is to resist rotation of the barrels. The upper part of the rib extension serves only to fill up the slot in the frame & plays no part in the actual bolting. The bolt should be held by it's bearing in the frame & it's fit against the lower portion of the slot holds the barrels shut. You can do as you please but personally I would prefer a good firm seating of the bolt against the lower part of the extension than to have it "Right of Center". As the bolt is wedge shaped (lower surface) closing up the slot will of course move the lever to the right, but actually worsens any problem, which it likely doesn't have anyway.
