How can i tell if i own a penny that is; 1912, 1918, 1919 = H? 1918, 1919 = KN? 1926 = mod effigy? 1945 = 9 double (2 dies)? 1953 = proof? ...i have more then one of all of the coins from those dates, but i do not know where to look for the things that i have put after '='... can anyone help?