Mike it has been done to Remington 1858 NMA Revs. A groove cut around the cylinder Pin to try hold more lube for the cyl. to turn longer and smoother.
I prefer to use my Lube pills, easier cheaper, works better, or you can do both I suppose.
Just to let you know Mike the confusion was that Colt arbors are theaded to the frame at the rear and held with a lock pin.