Owned 2 original, #s, St.Louis '69 RRs with A/C. Turquoise 330-horse, RR pie tin, dual snorkels. Every original #s '69 RR with A/C, regardless of trans, that I researched at the time had the turquoise 330 motor, not the orange 335. Every non-A/C '69 383 I've seen, and I mean hundreds, was the orange 335. The small unsilenced air cleaner was a orange/335 setup, and the dual snorkel was for turquoise/330 motors. Carter carbs on every original '69 RR 383 I've seen, though different model #s depending on trans, A/C, Calif & high altitude (Denver for example). Calif & high-altitude carbs had one central mixture screw. The RR pie tin fits both air cleaners, as did the other pie tins. Magnum was the Dodge marketing name, as previously stated, and would not be found on a Plymouth except by error.
For what it's worth, I've found that some '68s & '69s ran stronger than others, and not necessarily related to the 330/335 rating. For example, my A/C car was stronger than one of my non-A/C cars, and except for the A/C, seats & color they were basically identical. The 335 car "should" have been quicker, but wasn't. My St.Louis-built '68 was quicker & more responsive than my L.A.-built '68 car, too.