Electric Rear defrost?

I have a few questions for you's out there that know alot more about darts then me.

1. I found a 1975 Dart SE with electric rear defrost so I pulled the window but the switch was gone. Where did it go and what did it look like?

2. I found trunk filler panels for the trunk of 74 and up maybe earlier darts were these factory for SE cars? out of about 30 or more darts at they junkyard I was in I only found 2 sets (have both)

3. In 1975 they made a fuel saver system I found one car that I believe had it and pulled the entire wiring harness and a part for vacuum to control it. Is this system any good and worth installing on a 74? I don't think 74's could even get it.

4. My 1975 Valiant Brougham has a spedomenter in kilometers is this factory?

5. Anyone know where there is a good place to pick up A/c parts? I got a a/c control box and all the components for the a/c unit of a 318 but some of the fittings twisted off and the compressor is seized so I need to fix/replace them along with all the hoses

Thanks for any and all help If you want to see pictures of the yard let me know.

Dan