My pic was taken before I dismantled the truck. When I put everything back together, I actually did install the spring opposite from that- on the back side of the plate, slipping it over the long barreled nut, because my '51 GMC in my front yard has just the one spring behind the plate as well. The whole assembly seems to work fine either way though. There are some odd things about my '50 3600, like the radiator surround mount is the earlier 1949 two-hole style.
Marzach, the spring on the pedal shaft is a much stouter spring, and at present it is installed inside the cab, on the pedal shaft between the bracket and the firewall (hard to see, but as in this pic):
pedal shaft springThanks for the info guys!