They saw combat, but only as prototypes. An order was placed by the LW command, if my books are to be believed, but IIRC, the war was over before the factories were even completed, so there was never an actual production run, just a few armed prototypes which were tested briefly, in late March or early April of '45.
I seriously doubt it would get added, and would require heavy perking. After all, resistance was futile, so it could prove very imbalancing if it were added.
Referring to the Borg Cube (Borgen UberKuben in German), not the Spitfires in that same pic.