Bob,
I posted a N309 with Bill Jones His Cut Plug stamped on the back in a thread a couple pages back here's the link:
http://www.network54.com/Forum/526604/thread/1231882727/last-1231883353/Unexpected++card+backs..
I've seen this (Bill Jones) listed as a distributor of some other N cards that came from multiple companies. As I think about it, that's the only place I've seen reference to Bill Jones His Cut Plug. Would/might this be another company to associate with these cards.
Also in the same picture is a an N50 ship with a Sir Toby Cut Plug back. I remember an earlier thread listing the different companies that distributed the N50s that did not inlcude Sir Toby as a manufacturer.. same question as above for the N50 card.
Thanks,
Greg