Hi Harry,
Here is information from my 55 first series truck. Hope it is relevant to you. The stop light switch points to the right or passenger side. My truck also has a very specific embossed section the brake switch mounts to.
This page is from the 54 shop manual. It shows the brake switch pointing also to the right or passenger side of truck.
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm1238.html If you have the 53 manual it may have a similar diagram.
Great job identifying the issue and posting relevant pages in the FAM.
