A good discussion on Smith hammer guns appears on pages 103 - 106 of the new L.C.Smith book "The Legend Lives". The only thing that changed in 1898 was the literature discontinued the prefix "Quality" before the grade designation. Hunter Arms catalogs as late as 1913 still listed the entire lineup AA - F with corresponding prices. Subsequent price list and catalogs @1917 listed only Grade F & FF, however they contained a statement that "The higher grades were available on a special order basis". Your 17,xxx SN hammer gun could have been made either between 1884-1888 or after 1918. See page 523 in the referenced book. If you will look on page 104 of same you should be able to identify which of the two dates is correct from an examination of the lockplates on your gun. Good Luck !!