Competition Legalities of a Drilled and Tapped 1903A3?

[BigEd63]

A couple of years ago I bought and have been "un-bubbaing" a Remington 1903-A3.
The biggest issue is that as the title says is it being drilled and tapped.
Questions:
1. Is it a totally lost cause for competition use?
2. Is just installing plug screws with a high strength/heat adhesive smoothing out refinishing good enough?
3. If No to #2 would filling in the holes with either a proper welder and re heat treat and finish work?
4. Or make a 1903-A4 wannabe out of it?
Or...???