Yes on unison seats and they look complete. The pass side seat bottom will lift up and out and the back cushion is bolted at the bottom and has clips it hangs from on the back of the cab.
H-M linkage appears to be all there and correct.
Brown is a factory marking showing truck color off the line. Mine says transport written the same way as it has a transport blue lower body color.
The switch to the left of steering column appears to be an accessory turn signal setup. My bet is the extra turn signal lights were part of the kit and simplified the installation.
I think that will make you a fun project and a great truck!
