Basically, all I know of Richard McCoy is what I read in Calame and Rhodes book, with one hefty interview with Russ in 2008, which complimented Russ' general view of things. He still firmly believed that McCoy was Cooper.
A couple of things have come up for me, and us, in the past few days:
1. Credit cards. There is scanty information in the book on the subject of McCoy's credit cards, and his alleged possession of $8-12,000. They are unsupported statements made by an investigator named Theisen. (p.144-145.) This is a section of the book that is not well written, often murky, and flooded with information that needs to be more concisely presented.
2. Knowledge of Cooper. Along those lines, it is very unclear to me why Calame never talked to McCoy about Cooper. Further, the book does not discuss any efforts by LE to make a deal with McCoy on his skyjacking in exchange for information on Cooper heist, even though Georger says that offers were made. By whom is unknown, though. Yet, it would seem that making a deal is a no-brainer. We see that done all the time in cops shows on TV, and why it wasn't done in this case is baffling.
3. Yes, it is my understanding from the book that McCoy did tell Judge Ritter, when the latter asked McCoy if he did the Cooper skyjacking and is the only one to do so, appparently, McCoy answered: "I don't want to talk to you about it." This implies to me that McCoy had some level of knowledge about the Cooper case. Why he didn't use that knowledge as a bargaining chip with LE is a mystery, too.