No, I did not research on this, but feedback comments on bottom of the blog post suggests there were some exchanges that caused some further examination. I never said this is the "source" but it is possible it is. He certainly would have had access to any available data. And he would not be restricted about talking about it due to "legal settlements".
I found the following at Open Secrets. Not sure this is the same Steven C Anderson, but seems likely. The world of lobbying/trade associations is somewhat incestuous.
Open Secrets info hasn’t been update yet to reflect the FEC Oct 2011 reports.
McCain, John ANDERSON, STEVEN C MR
ALEXANDRIA,VA 22313 NATIONAL ASSOCIATION OF CHAIN DRUG 6/30/08 $2,300