We do have a few officers that are allowed to carry the 229. If an officer has small hands then the 226 might be too big or the trigger reach might not be right, then they can carry a 229 (and if I remember correctly I think a few might even have a 225). The bottom line is that they have to be Sigs.I know a Dallas detective that carries a 229.
Detectives fall into a different category too as they are allowed to have two primary weapons. For example, when my wife worked in a detective bureau she was authorized to carry her G17 as her primary weapon (this is what she carried in her Sam Browne) but she also could have carried a G19 as her primary weapon when she was dressed in plainclothes. Same with the Sigs - I could get authorization to carry both a 226 and a 229 if I was a detective.
One thing I can assure you of is that he was not carrying a 40 caliber 229. The only calibers that we are authorized for are 9mm & .357 Sig in our primary weapons, while .380 is OK in approved back-up weapons. The very few revolver shooters that we still have on the department can carry .38 Special or .357 magnum.