Since you are basically going to paint the gun, just fill that area with JB Weld, sand it smooth and paint.

Send it to Browning for a new stock and blue job. The worst thing you could do is to paint it or put some kind of "Coating" on it. The "coatings" chip and look worse than hammered sh!#. Painting or coating a Browning is like rattle can painting a Perazzi. Don't waste your money on that crap. Do it right and treat that fine shotgun right. You'll have a fine piece of quality for you and your heirs.

After having it re-blued, have a couple of steel or brass panels made up with your name, or maybe hunting scenes on them, then have them permanently attached so that they cover the lettering.

Then everyone will think that YOU are the idiot - but it will look a lot better than it does now.

You could always go the identity theft route and have planty of money for new guns! My grandfather did the same to his guns years ago. I still question that. Like my dad said, now they stole your gun and your SSN!

I was thinking along the same lines, Bondo the cerakote the sucker.

Since you're going to cerakote, file the area flush, sandblast, fill with silver solder, paint and be done.

Used smooth bore slug barrel, $125

I have one that was worse than that, I filed, filled and shotpeened the top of the receiver, added the Browning Stalker stocks and a 28" Invector + barrel, then coated the exterior metal with Burnt Bronze and the interior parts with Black T. You'd never know it wasn't factory other than the color and shotpeening.

i just used some of the duracoat filler on a 742 receiver and it did the job
there is a filler that they use in body work we always called it spot putty
duracoat is not hard to do.i got on e-bay and bought a compressor,air brush,
and my duracoat supplies for less than $100 and it turned out nice.
good luck with your classic

It's your gun so you can do what you want, just as it was the other fellows gun before. What's the point of sanding it down or filling it in? You don't like the looks? You want to protect the SSN? I say just leave it as it is and use it for what it will always be, just a shooter. I wouldn't put another dime in it personally.

FWIW, if you decide to remove the numbers, I would recommend finding a 'smith with a surface grinder instead of trying to mill it.