Difference between early and late sedan rear seat

Putting new seat covers on my ?80 seats and I?m now discovering the rear seat changed at some point. The later rear center armrest/pull down is longer than the early one and the late mounts are on the outside and the early mounts are on the inside. I want to swap the cover from one armrest to the other but it?s not gonna fit properly since it?s longer. What can I do other than find the later rear upper seat foam?

Do you have fabric from a later model rear back cushion you want to swap to an early style rear seat back foam?

Yes late fabric early seat foam. Didn't know center armrest changed between early and late.

If it’s just the armrest that is the difference, could you cut some of the foam out of the later seat back and then just get an early longer armrest foam to fill in the blank? I think I have an early armrest I’d be happy to send you. I actually have the whole back seat, but shipping the armrest only would be a lot more reasonable.

I have the armrest but there comes problem #2, the early and late ones mount differently in the center