I think you're right on the different 'type' of bows (not just the number of bows).
From what I think I'm finding out, the 70-71 5 bows had to use clips for the bows (the ends of the bows are straight and fit into the pockets of the clips),
whereas on 4 bow 71-74 (my 74). the ends of the bows have a bend which fit into predrilled holes?
On my 74, I do have 5 sets of 'holes' for bows (not sure the straight end bows would stay in place), but no place I can see to mount the clips...(i've attached pics of my 74)
All headliners I'm finding are around $80 and up, so if you have a $40 source, let me know. thks
So back to square one, as I have a 70 headliner that I don't think I can fit into my 74 which has no headliner or bows today....