Lloyd -
I checked the '69 AIM for the rear axle, page 65. It appears there was a production change to the clip - see note "17". Unfortunately, the copy quality of the AIM is poor and I can't make out the date when the change happened. I also checked the '68 AIM, but I couldn't quite make out the clip used but something definitely changed between '68 and '69 as the engineering drawings changed.
So it's very likely the clip on your rear axle is the original production clip which appears to be the same as the other translucent blue brake line clips.
Hans