Bane damage does a race check on the mob.
It is posible that things that dont look like a grimling can be flagged as a gremling. VI has a way of makeing sure no player on the game knows which is flagged what. Safe assumption is yes if it looks like a Gremmy, smells like a gremmy this bane will take effect.
In the item listed, it makes this hammer 14 32 against gremlings ratio is 2.286. Centi warr hammer is 2.133. I personaly would pick the ceinti hammer but for kicks i would keep the gremmy hammer in the bank for cr and such.
My wife wants the 2hs of Gremmy slaying, hehe the first 2hs looking weapon that bst can use. Talk about confusing &)

