I have a late model (1965 ish) .22 Mark 3 in very good condition. I am debating whether to take off the spot welded strip that serves as a scope mount, file off all signs of the spot welds, mill two 60 degree scope mounting grooves in the cylinder 10mm apart and then re-blue the cylinder. I'm sure I can do this work sufficiently competently that it will look as if it came that way from the factory.

My question is, if I go ahead, will the modification increase or decrease the value of the gun.