Very, very sure. All loricariids of this size, regardless of diet, produce a healthy amount of waste. Royals seem to produce more because their fecal matter is loose and tends to disperse all over the place (non solid waste is heartily produced too).
He is very correct. They were once thought to be a panaque species, but are in fact not. They are in the ancistrini genus. COL is right on this one, he knows his plecos very well.