Leon Crist,
I think the QC2-93 publication is a list of "recommendations" written for companies, to help them write procedures for training in-house inspectors.
If the job spec./code refrences a particular document, that is the document you need to work to.(even if it is out of date) I get jobs in our shop that the spec. refrences AWS D1.1:98 edition, but the 2002 edition is latest release. I'm only held to the requirements of the 98 edition on that job, unless they say "98 edition or latest". Then I need to work to the latest release of D1.1.
I don't think they would sell you a book that is out of date, but I've been wrong before.
Hope this helps,
John Wright