There are business strike buffalo nickels which have been produced from discarded or left over matte proof dies. These are easy to identify and in my opinion are variety coins!! To identify the reverse matte proof die, look for a straight line on the reverse rim to the left of the buffalo, at about 8:30. Once you seen one it is easy to recognize. Problem with trying to find one of these coins in an ngc or pcgs slab is the ngc pronged holder pretty much covers up this diagnostic and the horrible ragged pcgs rubber insert does the same thing. You will have better luck finding one of these raw. I first became aware of this diagnostic for matte proof reverse dies from Scott Travers book “Coin Collectors’ Survival Manual” which has been out in a number of revisions for well over 15 years I believe. Scott says that this diagnostic exists for all 1913 type 2, 1914, and 1915 buffalo nickel proofs. And I have also located a single specimen of the 1916 buffalo in gem ms65 which has this straight line. A worthwhile variety to look for in my opinion. The business strike coins from the matte proof reverse dies seem to be very scarce. (Buffalo nickel drawing provided by my daughter, Nicole Longfellow and photo provided by my friend Ron Pope — author of the Abraded Die Varieties for Buffalo Nickels.) Tom Arch — ebay user id buffnixx
Click on either of the above to view a larger image.
Edited to add sketch, April 4, 2011.
Edited April 5, 2011, to add image of 1913 Type 2 proof with die marker, contributed by coinquest1961, aka, Ron Pope.