well as far as i know unless they have incorporated an electrical circuit in addition... the anti-restart is usually limited to the keyswitch.

It is a mechanical lock inside the keyswitch that is activated when the key is turned to the start position and only unlocks when the key is turned back to the off position.
So in effect...
when you go from 'off' to 'run' and then from 'run' to 'start' position the lock goes in place so when you go back to 'run' position it prevents you from turning the key back to the 'start' position.
The only way that is released so you can turn it back to 'start' position is to turn the key to the 'off' position, the internal lock is then reset so the key can be turned back to the 'start' position during the next starting sequence.

Now if by chance there is an electrical module that controls anti start that would only be active while the engine is running i would think. So... if the engine is not running you would most likely see the circuit inactive.
I would have to have the manual to be certain but that seems like the logical way it might work in my opinion. Based on the model and serial number of the truck you mentioned the anti start modules (electrical) were not being used back then, at least not that i can remember. :o)