Think of it this way: VFO - IF = RF. Does this result in sideband inversion? (hint: -IF + VFO. It it positive or negative?) Why don't you try it and see what happens. If you get nothing but garble, then the answer is "no...it does not.
If the results are clear signals, then you must decide if the LSB is being inverted, or is it truly USB. Remember that the ordinary condition by convention is that the LSB on 20m is garble or non-existent. Therefore you must hear USB inverted to LSB or true USB for intelligibility. Be aware of AM; test your results through several different QSOs.
Actually, it doesn't matter which it is -- as long as communication takes place.
