Neighbour Hood Watch was a real thing, even here on the West Coast....Tig welder (a good one) could fill the holes then you'd have to file, draw file and repolish and blue or color case the whole receiver.
Back in the 1970's police here in the maritimes went house to house offering to engrave valuables with an electro pencil. Buggered up a lot of nice guns. Still see them now and again. Called it Operation Identification, I think.
I agree, leave it.I'd leave it as is.
If you can't live with it, sell it and buy another. It is what it is.
It was a thing back in the day. The concern was "this is one of several hundred thousand made, if I lose it and it's found, or if it's stolen and the police locate it, how else am I to prove it's mine?" I have several specimens with said SIN number on them. Some of them are hand downs, others I've picked up along the way.why would someone put their sin # on a firearm?



























