Correct.
Around that time, Colt was making a long list of limited run pistols using various combinations of Government Model, Commander, and Officer's slides and frames.
These had names like Tank Commander, Night Commander, Night Officer's, etc. etc. etc.
The name of the model doesn't necessarily tell you what the actual slide and frame combination were.
In your case, it's a Commander size frame with an Officer's size slide.
The correct magazine is a standard Government Model or Commander 7 or 8 shot magazine.