Driftwod;
Provisional/Temporary proof was for the bbl blank only. This was applied to the rough tube prior to final configuration & was for the purpose of weeding out faulty blanks before putting a lot of work in them. Was often described as the "Gunmaker's Proof".
Definitive/Final proof was for the gun complete except for final polishing/finishing ( no substantial metal left to be removed). This was considered the "Shooter's Proof".

Miller/TN
I Didn't Say Everything I Said, Yogi Berra