Interesting discussion. I would think the team bike would have the thinner gauge “professional” 531 tubing and the other the “standard” gauge 531. Here is some Reynolds info Reynolds Tubing Catalogs/Manuals
As others have said, Raleigh catalogs did not always match what was produced. Also remember they were generally written by marketing people.
As for reinforcements, I’ve seen some brake bridges and fork crown lugs that had a greater area of contact thus “ reinforced.” Could it be something like this?