When Harley Quinn walks into the Clocktower, she is wearing a red sweater pattern with black harlequin diamonds. The harlequin diamond is a staple motif of her costumes in the comics and in certain live-action portrayals; her colors nearly always include black and red in all portrayals.
When Huntress finds Gibson in No Man's Land, the hand movements he makes are American Sign Language alphabet letters, but they do not appear to make any sense in the order he uses them (apparently SNTNMP).
Last episode of the series.