Good question, the early Op pre-war and post-war from 1927 to 1969 were both made in 2" and are very scarce, but to my knowledge none were made in 3". In my travels I've only seen one 2"er, but at the time had no need for a big short barrel revolver. Check with dfariswheel, who seems to be the only resident expert we have hanging around the forum right now. He probably won't like me calling him an expert. Dick
I'm NOT an expert, but I did stay in Sally's No-Tell Motel last night.
The Official Police was available in 2", 4", 5", and 6" barrels, with the 2" and 5" the rarest, the 2" rarest of all.
During WWII Colt made the Commando, a war-time version of the Official Police with a 2" or 4" barrels, with possibly/probably some 6" models.
The only 3" I've ever seen were custom cutdowns, with one possibly a post-war Custom Shop model. I never heard if the owner ever contacted Colt to see if it was.
Most of the 3" I saw LOOKED like non-factory cutdowns, but that one at least looked like it could have been factory.
One of the non-factory guns also had the grips rounded off like a Detective Special.