Pic a nic --- sure looks like an inverted mint mark to me. I suppose you could email Ron Pope...he has written a book on Abraded Die Varieties (and other anomolies) of the Buffalo Nickel as well as helping to write the Authoratative Reference on Buffalo Nickels, along with Kevin Flynn and John Wexler. His email is
coinquest_sixtyone@yahoo.com ... he has it in his Abraded Die Varieties book and offers to look at any possible varieties. You would need to attach the best pics possible. Perhaps he could help shed some light on this...whether it is really what it looks like... is it rare or common? etc...
