1971 duster late built car spring 1971

Im trying to determine if my car is a 4 bow or 6 bow car. I found this info on a website that sells headliners:

Early 1971 Dusters were manufactured with 6 bows, and Late 1971 Dusters were manufactured with 4 bows holding up the headliner (inside roof cover).

According to this my car should be a 4 bow but the roof side braces are drilled with 3 little holes in 6 places on each side. Doesnt that make it a 6 bow??