Here are some pictures and what I have found, that being said there is very little in the factory documentation. The first is a tire iron I found under the seat in three large trucks, all were identical and fit the factory lugs (never found a jack for a large truck).
https://www.flickr.com/photos/advance-design_parts_co/15217351364/in/album-72157631868452754/
Here is what I assembled for my truck. I have found three of these jacks w/folding handle in parts trucks. This jack was produced and used in a variety of applications by GM into the early 70’s. These jacks have no markings, stamps, etc.
https://www.flickr.com/photos/advance-design_parts_co/8129502216/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/16079459486/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/16105224175/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/45119759105/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/46031555731/in/album-72157631868452754/
I found jacks in the following, 1949, 1951, and a 1953 that had burned. I will look in my GMC Master Parts Book as it has additional information when I find it. I would think that these like the hand tools were left in garages and sheds over time, thus they are rare items.