Yes they did, but Glock has the decision under protest.
I think they will stay with SIG due to the interchangeability of slides, barrels, and frames. Basically the chassis is the issued weapon and the armorer can fix you up with what frame size is best for your hand.
I own Glocks and Sigs, and back in the good 'ol days we shot Bertta 92s. Anything is an upgrade from the 92. Sig or Glock, doesn't matter.
The fact that the trigger pull is the same if shooting the first round or the last will help some of these officers qualify. It will also be WAY easier to train a giant mass of folks who will likely only fire their 320 once a year at a paper target....