Will you love me forever?

Just kidding my actual question is;

Other than the cloth covering on the seats is there anything unique about the back seats in an Si? I am wondering if the Si cloth will fit the frame/foam from another hatch.

 

I swapped out an EF SI interior into my EF hatch with no issues. I did not try to remove the cloth from the SI and re-cover the DX rear seat but instead just swapped it out foam and all.
I hope this helps.

 

I found the answer to my own question, all 1990 and 1991 Civic Hatchback rear seat foam is the same. I used this process to figure it out.