Ron, I think what Sheppard & Mees found was that Bromide works well as an anti-foggant in p-Aminophenol devlopers, but with some developers/developing agents at a higher level the Bromide suppresses overall development, Metol & MQ developers are prone to this.
Anyway Rodinal has been using a combination of Bromide and an organic anti-foggant for over 64 years, so this seems to dispel the speculative statement. How much they might have raised it by when the reformulated is less important.
People who prefer the older Calbe R09 version claim it's cleaner working, it's probable the extra hydroxide in Rodinal may lead to a higher base fog, but in all honesty Agfa Rodinal is a superb developer and with Tmax 100 or Agfapan 100 delivers cleaner sharper negatives than ID-11/D76 IMO. It was my main developer for personal work 35mm to LF for about 19n years.
Was Kodinol, the Kodak p-Aminophenol concentrated developer, ever sold in the US. There's nothing on the internet at all, but it's listed in my Kodak UK 40's & 50's books.