ARC-## is the same nomenclature that Battletech uses, if it matters.
Did they copyright their nomenclatures? It might be beneficial to delineate CAV from BT. Of course, this only matters where the CAV and Mech names are the same, like the Archer.
I would lean toward manufacturer - that way, if the model was stolen or redesigned by another manufacturer (or home-grown), then there'd be a natural change.