Either way will solve your problem, if you're going to get more Norwich or CZ/DW barrel/shroud sets; the pin would solve future problems. Interesting that Norwich changed the spec's as I've got shrouds from both Palmer and Monson and they all interchange on my Monson gun. I do know that Norwich built all new milling machines for their line of DW's as the palmer machines were from Monson and quite dated. CZ acquired all the original Norwich machines.