All 1913, 1914, and 1915 Buffs, even the proofs, show a weak "LIBERTY." The master die was re-worked in 1916 and liberty was strengthened.
There are a couple of minor doubled dies on both the 1913 Var 1 and Var 2 coins but the one to keep an eye out for is the 1913 Var 1 3 1/2 legged. The 1913-S Var 1 2 feather is also a goodie. I've written a book on the abraded die varieties (2 feather; 3 1/2 legged, etc.) for this series and therein I've listed 27 different 2 feathers and eight different dates for the 3 1/2 legged coins.