Manny the Mesopotamian tells Barbara that he is cutting his commission in order to make the deal with King Tut. However, Tut stole the money to pay for the property - there would be no reason for him to have negotiated the price low enough to cut into Manny's commission. Further, Manny specifically states that Tut doesn't haggle.
The foreman tells Tut that the cave is lined with something too hard to blast through, yet the gang easily break through in the mine car.
Batman references making King Tut raise his voice "3 decibels above high-C." Decibels are loudness and C is a pitch.
As an inpatient in a psychiatric hospital, King Tut/Professor McElroy would be required to wear hospital-issued clothing, not his King Tut paraphernalia.
King Tut and his gang attempt escape from the Terrific Trio by descending into the mine, which to their knowledge is a dead end.