[Jim McDougall]

This is beautiful!!! and as you say, this kind of rugged charm is outstanding, a working weapon.
This is effectively a 'rapier' (obviously by the cup hilt form semantically associated in true rapiers). It is actually an 'arming sword' and typically used by Spanish colonial forces in the Caribbean regions and 'Spanish Main' (Central and South America off Gulf).

It is most definitely 18th century, probably earlier in century, and as with colonial weapons, refurbished over long working lives.
The wire wrap and posts are missing, and as you have noted this was an affectation typically on the 'bilbo' which was basically a 1728 'pattern' (though in use before through the century).

The guardopolvo (=dust cover) does not exist in these, they were a decorative plate at the blade junction inside the cup.

These were typically carried by infantry forces in the colonies and existed concurrently with the bilbo. As these colonial forces were remote they seldom had stringent regulation, and swords were more tradition than weapon as a rule.

Outstanding weapon!! and these are not often seen available, even less than bilbos.