"The surviving House C figures wear a pectoral with an eroded day sign and the number seven. The Hieroglyphic Stairway records the sacrifice of six captives on the day 7 Chuwen. The kneeling figures on the substructure of House C represent these six sacrificed lords. The day worn by the balustrade figure on the Hieroglyphic stairs surely refers to this 7 Chuwen sacrifice.
One balustrade figure on the Temple of the Inscriptions wears the number six over a day sign, while the other has a thirteen and a day sign. It happens that the sacrifice mentioned in House C was followed six days later by the arrival of Nun-Bak-Chak, the king of Tikal who had recently been forced into exile by Kalak'mul. This memorable visit fell of 13 Kaban. We think that the figures on the balustrades of the Temple of the Inscriptions and House C commemorate these momentous days on their pectorals..."
Linda Schele & Peter Mathews, The Code of King: The Language of Seven Sacred Maya Temples and Tombs, p. 101