Far from an expert but I can tell you its run was from 1908-1927 and the serials ran from 291,000 to 540,000 (about). Also in 1928 it became the Official Police which ran to 1969.
One would guess yours is an early one. I bought one in .32-20 WCF a few weeks ago for $200.00 (admittedly low end for a shooter). As always condition and collector interest will rule the day.