Jeremy,
As my fish ID book (Marine Fishes of the GBR and South East Asia by Gerry Allen) puts it, the giant salmon catfish has one long and two short barbells near the front of the mouth, while the other "smaller salmon catfish" as the book puts it have 3 long barbells. However, it is very difficult to determine between the species.
I'll take a stab and go that they are Giant Salmon Catfish aswell.