HELP! What the heck is this?

Looks like a seatbelt interlock controller to me. One year only ('74) because of the headaches it caused. If the car starts and runs, very carefully put it back and leave it alone. Loss of dash lights is either a corroded connection on the instrument panel, all the bulbs are blown, or the rheostat in the light switch is bad. Could also be a blown brake light fuse. Your loss of temp gauge and fuel gauge is more than likely a bad instrument panel regulator. Lots of threads here on that subject if you do a search. Hope this helps.