AMK B-13202 AMK describes it as 8.25" OAL (over all length).
Ford number C1VF-19B915-A (per AMK)
Bingo - maybe. It's shown as used in the air conditioning evaporator hose retaining for a 1968 Shelby GT350 only (4 required). The pin is shown as part of the AMK drawing.
The rivet or pin is required to secure the bundle and therefore it is part of the strap.
If so, AMK would have stated as such.
The shorter strap secures to the T-stud.
Please identify "T-stud".
I believe the use of the longer strap was either a running change or a line change.
If that were the case, then this "running change" would/should be reflected in the 1969 and on Assembly drawing.
It is clear from the pictures shown this strap applies to both 68 Mustangs and Cougars.
That's an assumption, which may not pass an extensive judging event.
Jim