Fabrique Nationale or FN is the maker.
Browning.com has sn data on their web site under customer service.
The rifles action was made in belgium by FN they were suplied to High Standard who actually built the rifles for Sears in the late 40s up to late 50s these are high quality and sought after rifles in excelent condition they can easily bring 400 to 500 dollars.
Belgium
50-1000 usd
Probably an assembly number.
Sometimes by the complete sn, sometimes by the action and features.
Browning's web site has what you are looking for.
For a specific answer, please provide the model number. Most guns stopped production in Belgium in the 1970.
It will be stamped into the action (the cylindrical part that encloses the bolt)
1965 mauser action safari grade
It will be stamped right into the action. (The part the bolt slides back and forth in)
50-350 usd