Differences in Duster back seats

I have two rear seat bottoms, one is Feb of 70 and one I believe to be very late in the year 70. The early one has the front riser thats taller and hits the carpet hard. The other seat bottom the riser floats off the floor 2" or so, I can put my hand under the seat with it clipped in place. They both clip in just like they should. Is this just differnent vendors that mopar used? I want to use the one that floats off the floor because its the best core but I feal like its wrong. Any help guys?

What do you think guys? Can anyone help with this?

I'm not sure that Plymouth made the space Duster model(fold down rear seat) in 1970, if so maybe the higher, smaller one is for the other model

I ran into this problem with my 71 duster, found out the rear seat out of a 72 had a different size hump, had to find earlier correct seat

Friend of mine has a 73 duster now that I think about it. I should ask him if he can fit his hand underneeth.