A civilian scope. There was ONE reference to a few M8 apparently having been used on the M1903A4 sniper rifles (ref: Senich), but no proof is available, Pete is now deceased and no one else has turned up further evidence reference Poyer.
I had an M8, 330 and several original M73 scopes and a couple of original M1903A4 rifles, so I had looked into this.
Your cone turrets are the silent type. Although illustrated in the first manual for the M1903A4, the U.S. Army wanted the drum click type. So yours does not have the correct external appearance for the M1903A4 sniper rifle ("close but no cigar"). The U.S. also went with the fine cross-hairs.
The M8 is useful if someone is making a budget clone of an M1903A4 for re-enacting or simply for shooting, but not for a genuine M1903A4 as these are rare in Canada and they deserve a correct scope.
Value $100-150 Canadian?