Re: 65 Chevelle Bucket Seat
The factory installed that padding to eliminate/reduce wrinkling, especially where the seat cover wraps over the top. A little extra "fluff" to fill it out. I always install that extra cotton padding when restoring a set of bucket seats because that's the way the factory did it.
I think a lot of guys don't install it because it is never included with new foam or new covers. You have to purchase the cotton separately or re-use the original padding, which is usually not in the best condition.
It's a little extra work, but makes for a much nicer looking and proper restoration when done.
When I works, I works hard.
When I sits, I sits loose.
When I thinks, I falls asleep.
The '68 L79 Malibu survivor as found in Nov. 2014, in my profile pic.