This bayonet looks like the Swedish m/1775 but the blade has no fuller on the upper side, it is flat like the m/1747.
It was originally made to be mounted on the left side, but it has been modified for right side mounting, like most m/1747 bayonets were.
The shoulders are round just like m/1775 and onwards.
The original left side mounting and the flat upper side of the blade makes me think this is pre 1760.
This model was also found modified to a fencing bayonet. Same modified socket (left to right side mounting).