Question about sunvisor shoulder belts retainers

Can someone tell me what model car would have sunvisor shoulder belt retainer clips that have the numbers 10R and 10L stamped in them? I'm thinking some sort of 68 or 69 B-body as the clips in my Dart are stamped 1R and 1L and are somewhat smaller.

Does anyone know what years Chrysler used these retainers to hold the shoulder belts in place when not in use? I have done some checking and have determined the retainers are not for a 68 Superbee, 69 Road Runner, 69 Fury, 70 GTX (not sure if they even had them in 70) or 69 Dart. Possibly 68 or 69 Charger?

if i remember correctly i had them on my '71 road runner.

My 69 Dart has them.

Ooops, didn't see the 10 R & L.

The ones in my 69 Dart have 1R & 1L stamped in them. Hopefully, someone can tell me what the ones with 10 R&L stamped in them are for.