Turn signal pigtails for 1971 sharktooth grille

UPDATE: I need to talk to someone who really knows these grilles, because the housing has an arrow and the word "LOCK" on the back which would make me think it uses the twist lock style, but it also has 2 small screw holes at 6 and 12 o'clock like the screw on type would use. I'm wondering if there is some intermediate piece of plastic that goes between the housing and the pigtail.