Nobody's gonna use Sableye's evo anyway, Eviolite Sableye all the way
Even if he gets eviolite, his defenses are still easily broken trough, and his base 50 hp does not help. 97.5 sp. Def and 112.5 def arent super amaizing base stats. Evolving him would probably give him better abse stats anyway, and you wouldnt have to resort to using eviolite.