700r4 lockup question

[silversnail86]

Ok, I have an 86 c10 that originally had a 305 "ecu" motor. It now has a carbed 350 seems to drive ok but this is only second automagic I've ever owned.
I was cleaning up some wiring today and found a little vacuum controlled box that has 2 vacuum ports and 2 wires 1 blue and 1 yellow. yellow is coming up from the trans lockup dealybob on the back drivers side of the trans above the pan. I guess my question is How would I know if someone went with a non lockup convertor or installed a lockup kit or if it's just plain not hooked up? There are also 2 different electronic/vacuum deals on the firewall that are not hooked up they each have only one vacuum line. Thanks for any help!!