I think we're all novices when it comes to American Luger/Carbo-Jet.
Q: Where does the Swanson model fit in? A: right at the very tail end of production. So, yes, after Hy-Hunter. As I recall, this is confirmed by the info in Smith's.
Note: we had a long discussion about American Luger/Carbo-Jet on this forum many years ago which I presume they can still be found via searching.
In summary, unless more info/literature is found, I see the chronology breakdown as:
Var. 1: American Luger = no variable power.
Var. 2: Carbo-Jet (still marked "American Luger") variable power.
Var. 3: Swanson - Single shot, variable power, also marked "American Luger."
Sounds like you are missing Operating Instructions for Hy Hunter New Carbo-Jet Variably Power CO/2 Model V-822 Gas Pistol.
Here's the Fickr Album with everything I have. (click on the picture)