I can't agree. I have one of those engravers (as they are called now) and with a little practice I could follow the original marking under a re-finish to achieve exactly that effect.
However to me it is the London Proof marks that are the clincher that this rifle has been refinished. The "Armed Arm" holding a Seax on the barrel is is part of the London Proof mark and it has clearly been applied prior to the current finish. There are just a few glints on some numbers on the rest of the Proof marks that seem to have been caused by loss of some finish.