[TKCR]

The 79 CarmineRed is not the same as the 81-83 CarmineRed. Close but the colors are different.
Also if the 79 belts are plastic buckle, which I believe they are. And the 82 belts are metal buckles, then the tongue on the 79 retractor will not latch to the metal buckles. They are a re different size. See the photos.
The tongue on the plastic buckle sets are long and narrow.
The tongue on the metal buckle sets are shorter and wider.
They will only work with the appropriate buckles.

Is there something wrong with just the left side? I do restore these belts for our trucks. Maybe I can just get your set restored for you. Check out the thread I have on restoring OEM seatbelts. Link is on my Signature.