Parker assigned number grade and letter grade at different times in their history. When letter grades came into use, number grades were still also used by Parker. A zero grade gun in the hammerless era is a V Grade. The PT mentioned in the discription of gun #82,608 in the Serialization Book signifies a Grade 1, PH Grade. There was no mention in the listing for #82608 that it is a zero grade gun. The gun was, as you estimated, made in 1894. An original 26" 12 gauge is a pretty scarce gun in that period.
