Jason(?),
The IL 83 list is a bit off from signage where it meets IL 50 near the Tri-State. I'm not sure what official maps or data/shapefiles indicate, but signage clearly shows IL 83 following 127th between Cal Sag Rd and IL 50/Cicero. GMSV backs up what I saw in the field (I was heading eastbound). OSM shows the signed alignment.