The row of rivet holes in the steps that the plans say should go through the F-724 vertical bulkhead... Are those rivet holes to be drilled supposed to match the existing side skin and vertical bulkhead rivet holes, thus replacing the flush the side skin rivets? Or are they in addition? If they're in addition, do I have to worry about placement modification from the step's plans to not interfere or chop any of the flush rivets, etc? Just double checking. Thanks!