S&W fumbled the model numbers with the 69xx series. As mentioned, the 6944 is a blue slide on an alloy frame. A stainless slide on an alloy frame which should be a 6943 is actually a 6946. There is no 6943 and there is no 69xx with a stainless frame.

Of course there's nothing to prevent someone from slapping a stainless slide(6946 or even 3953)on a 6944 frame.