Hey no problem.
ground "should" be a black one, its been a while since i have messed with car tail lights. Big trucks are different color grounds and messes me up sometimes
What i would do if it is messed up like you say is go to a local pull-a-part and get that harness off a donor truck and that way you know that it is good and least you wont have to patch it together. Those butt connectors will corrode later especially up North in saltier conditions and the things you fix now will cause you problems later.