Hello Mike, I had thought about these from the off. But i have since had information.
That GMC trucks that also Towed 1 Ton Ben Hur Trailers. Had a Pair of holes in their rear crossmember for the Aux chains. When the weather is a bit better, I will roll back my Collapsable garage. & check if this was also the case for dodges? It is interesting, that this question has never been raised before?.....
My findings will obviously be posted on here. For the benifit of others, who may have been thinking along similar lines. Towards towing a trailer.