...or at least I assume that they are '67 rear shoulder belts, I guess that is my question.

I was going through the garage, getting ready for another garage sale posting, and I came across what I was told may be a pair of rear shoulder belts and retractors. I don't remember when I pulled them out of the parts car (1988 or 89 I think) so I can't say for sure. The belts are short and the retractor housings are only labeled on the outside as L and R. The belt tags are as follows:

IRVING 1968
MODEL 327
36 A 67

Any ideas exactly what these are?

Thanks
Adivanman