Trying to get rear seat and backrest out and no luck, anybody have a suggestion? I had another 67 and I just pushed back and lifted up at same time and bench came out.

 

That's how you do it, there's a floor mounted notch bracket on each side, passenger foot area, that the seat latches into. You might have to give it a swift kick with your knee while lifting. The backrest has a hoop hanging down on each side that screws to the back raised floor area, but the seat bottom has to be out to get to them.