1967 bench seat repair questions

[arcticman]

Hello everyone,
I have several questions regarding my bench seat. I have 67 k1500 WS SWB
The seat is a bare bones seat with a minimal foam pad. Several of the spring straps are broken, (4) total I believe. I thought maybe I could weld them back together but it looks like over the years some of the actual coiled spring has come undone and is missing.
Questions:
1) Is there a company out there that makes replacement springs?
2) Is there any way to rebuild these seats?
3) Is the 1967 seat a "year specific seat"
4) I see American cushion has several foam options depending on what your truck is set up with can you interchange foam I.E. add 6" molded foam to a seat with a thin foam pad.
Thanks, Scott