Is there any Gorum worship in Absalom? It isn't listed as a major religion there, but does it exist at all? Officially in any books?
There are almost certainly people in Absalom who worship Gorum (likely mercenaries, bravos and adventurers), but there's probably not an actual, organized church of Gorum anywhere there. Absalom is a place of culture and commerce; martial valor is useful and can get you places, but it's not something Absalom enshrines in a way that would see it considered one of the city's notable faiths.