Yup, the Commander's are based on a Full Size frame, the Officers, or some of teh different Compacts are based on a shortened frame, but will also accept the full sized mags, they just stick out about .4".
I have carried full size mags for spares with guns that are built on the shorter frames. Obviously, the Officers (for the shorter frames) won't work in full sized guns but it's not a problem going the other way.