That is news and a surprise to me. I thought all C&Rs were listed specifically in the regs.
Read the law and the regulations. It is specifically stated that any firearm which can be proven to have been made 50 years prior to "today's date" is classified as a C&R by BATF. The specific listings, initially, were guns that were petitioned by individuals to have them reclassified as C&R's, some of which were LESS than 50 years old, some older. But the law actually reads that any gun 50 years old or older is automatically a C&R.
So... That means, as of today, August 20, 2011, you can use your C&R license to purchase any gun made prior to August 20, 1961.