Once the decision was made by the Calgary City Police Force to transition away from Webleys and before any decision on a replacement revolver was made, the brass made an 'anything goes - within reason' unwritten policy allowing personally owned sidearms to be carried, but they supposedly had to fit the issued uniform flap holsters. This was in effect for about 12 months or so up to when the chosen S&W 4" Model 10 .38 Specials started to be issued to uniform members.
In the interim, needless to say, quite a few holsters were 'slightly modified' or replaced, and I saw many instances of various Colt and S&W revolvers being carried, along with more exotic pieces such as Browning Hi-Powers, Lugers, various 1911 Colts including one with a nickel finish and pearl grips, and even one broomhandle Mauser. I personally carried my S&W 6" K-38.