May i come in ?
... Not that i am an expert
It is possible that the blade could have been from a plug bayonet ... although not necessarily.
The hilt, by no means, as it lacks the traditional necessary shape. Also the wrong material ... maybe from a classic dagger ?
The guard also looks more dagger like.
The scabbard hanging system too delicate for a plug bayonet ?
I wouldn't think that
SA being Spain Albacete fits in. Would quicker bet on owner's or maker's initials.
Where are these initials placed ? Could you come back with close pictures of those ?
Fernando