I have read that most of the pocket positives were in fact chambered in 32S&W long and marked 32 Colt New Police. It is not uncommon for revolvers to be offered as being 32 Colt when they are in fact chambered in the S&W round. They can be reamed out to take 32 SWL.
Howdy Again
You have to be a little bit more specific when you say 32 Colt. There were the 32 Short Colt and 32 Long Colt which used heeled bullets and the 32 New Police which did not. See the photo down below.
According to The Standard Catalog of Colt Firearms, the Pocket Positive was chambered for 32 Short Colt, 32 Long Colt, 32 Colt New Police, 32 S&W, and 32 S&W Long. I have no figures for how many were chambered for each cartridge.
The little Pocket Positive at the bottom of this photo was made in 1908. It is simply marked COLT D.A. 32 on the left side of the barrel, and Pocket Positive on the right side of the barrel. It is not marked for a specific caliber.
The chambers are bored straight through with one diameter without any chamber throats. The only box of cartridges I have that will fit into it is a box of 32 Short Colt. If I had a box of 32 Long Colt, they would most likely fit too, as long as the cartridges were not too long for the cylinder.
The larger gun at the top of the photo is a Police Positive 32, made in 1917. It is marked POLICE POSITIVE 32 POLICE CTG on the left side of the barrel, meaning 32 Colt New Police. Colt simply did not want to mark S&W on their revolvers, so they came up with the 32 New Police cartridge which is the same as the 32 S&W Long, with a slightly flatter bullet.
The 32 Short Colt and 32 Long Colt were cartridges that used an outside lubricated heeled bullet, meaning the outside diameter of the bullet was the same as the outside diameter of the cartridge case. 32 S&W, 32 S&W Long, and 32 Colt New Police cartridges will not chamber in this particular revolver because they use a bullet that that fits inside the cartridge case, like most modern cartridges. In other words, the cases of these cartridges are too wide and will not fit into the chambers. I suppose yes, if the chambers were reamed for 32 S&W Long, then it could fire all three of those cartridges, but I have no intention of doing that.
The cartridges in this photo, left to right, are 32 Short Colt, 32 S&W, 32 S&W Long, and 32 Colt New Police. You can see that the 32 Short Colt case is the same diameter as the bullet, whereas the other three cartridges have slightly wider cases. The cartridge case of the 32 Short Colts is running around .315 in diameter. The cases for the other three cartridges are all running around .331 - .333, so they will not chamber in this gun.