Just acquired a similar spadroon, minus the 5 balls.
I suspect the curved blade and brass guards point towards naval use. Looks like I'll need to add a brass ring for the sword knot. 62cm. Blade. These appear to be from the period 1780-1790, straight ones were used by the British infantry officers, I suspect the curved variants were more useful in the cut, and more favored by the naval officers. These were 'standardized' in 1796 and the 1796 straight infantry spadroon was widely considered a poor cutter (and a poor thruster).