I stand corrected and am sorry to have led you wrong.

I have never seen that on a modern production gun. To be frank that seems like a strange way of doing things because when they set the ribs they must have to clamp everything including the monoblock and barrels up, it must all be waving around like a prick in a shirtsleeve. I just cannot see the sense in it, if you are building production mono's then a squirt of liquid CO2 or nitrogen and slip the tubes in to a room temp block and they are there for ever..
Ah well they must have their reasons.

Again I apologise if I caused you additional work.

Regards