Swedish M41 sniper questions

I looked over a Swedish mauser M41 missing its mount and scope. All visible numbers were matching except cleaning rod. No import marking.

Any links to info on m41 conversions would be appreciated.

Is there a recorded database of sniper serial numbers?

Does anybody know ATF's position on the drilled through serial numbers? (Anybody who has had one with the mount removed should understand).

Thanks in advance.

I'm rusty and not remembering how to edit my original posting. The mounting hole pattern is for a M41B

A lot of those rifles came into Canada thirty or so years ago. Some without scopes, some without even bases. I had a stripped barrelled receiver at one point with the flat and two up one down holes IIRC, also a minty M41 a few years back which went south. No import marks AFAIK on our imports then so if the one you're looking at has none it may be an import from Canada.