Referring to how the top fabric is attached to the frame at bows #2 and #3.
In 67-68 (well, at least 68 for sure) Bow #2 and #3 have a pocket that is attached to the top fabric. A metal strip, about 1/4" wide x 3/32" thick x width of the top long is inserted into the pocket attached to the top fabric. The fabric sits on top of the bow and 4 screws hold the top fabric, via the "listing" in the pocket, to the frame. Reduces "ballooning" of the top while driving.
The referenced car had no fabric pockets across the top at bows 2 and 3, just a secondary fabric flap (think the edge of the top folded under itself along the length over the window) that was screwed to the bows at the outside edges. Owner says it is factory.
Not referring to the side hold down cables that run the length of the side rails (which do differ in quite a few ways from early 65 to 68... stud vs. spring attachment at rear, screwed clip vs. ball on end of wire at front).
On the road and can't take any photos of my '68 to clarify.