Anybody know what these are?
I'm thinking something to do with vista cruiser seat belts?

 

For the shoulder strap? it would fold and go under this. I know they used something like this in 1972, not sure if they had them in 1971. All A-body, not just the Vista Cruiser. Now that I think about it, not sure maybe the full sized used these too.

 

Wow that was quick! So all A body cars and maybe full size too. What do you call them?

 

Not sure what its called. But I've got some in the garage, I'll try to dig one out to compare with your picture to make sure that's what these are.

John