'70 dart swinger vs duster back seat?

rear seats are not the same between the two body styles. 4 dr is also different.
I realize 4 door rear seats are different shape at the corners. I was hoping to change covers, but the man I am getting parts from has a huge old boneyard, I will take my seat and hopefully get a little trade in value. I have kept the seat for last couple years thinking I might pick up a good dart or swinger and need it, but.....!! I have seen a few but wife wonder why I need more than 5 old Mopars!!??? lol