NEHI Cool Box

This is a true "barn" find. I am trying to understand how much of this is original. The Cool box has signage on all 4 sides, with one side being pretty rough, but the other 3 are reasonable as seen in pics. front and back are same and the ends are also the same(different from front and back). It is roughly 30inches wide and appears to have original insulation (pic 2). The fold back lid is very heavy and there is a drain in the bottom of the box. The biggest mystery surrounds the base (pic 4) it appears to have had wheels at some point, you can see the bracket that the wheel would have went into, but it really looks more homemade than the rest of the cooler any help is greatly appreciated...If anyone can point me to additional locations to learn more about this that would be great too.