Police Positive - 38 Special questions

[Errkola]

OK, this friend of mine has this PP in 38 special. it was given new (manufacture date is 1917 or '18) to a criminal judge back in the '20s and used very little since then. Other than the grip straps the finish on this gun is 98%+. As I understand it there is a Police Positive Special as well, chambered in 38 special. Apparently the cylinder on the Police Positive is not long enough to fit a 38 special, at least that was what I was told, but I am not sure how to explain this pistol. Please someone give me the straight skinny on this pistol as I am tired of debating it.

Also, what is the approx. value of this pistol at current market?