Can someone identify these buckets for me?

[BradE]

I received these bucket seats for free from a guy parting out a '70 c-10. They were obviously not the original seats, but I'm curious to know what they came out of? I figure all you car buffs out there could help me out..........? The blue one is the original color, the black one has been painted/dyed. They were bolted directly in the truck, but rode a little low. I want to re-upholster them eventually and replace the bench seat. Thanks in advance for any and all help!!