Yes, the prior PC unit was a stepper motor unit/box. It was mounted to the lh fender apron and had a solid connection to the throttle linkage, as I recall. The first time I remember seeing the turn signal stalk-controlled unit was in the '68 model year. What is pictured would be the later Chrysler unit, with a cable connection to the carb linkage at the carb AND which is run by vacuum rather than a stepper motor (electro-mechanical).
As we are speaking of what would have been a '65 model year OEM system, perhaps the later Dana/Perfect Circle combination hadn't happened yet?
To me, there were some detail differences in the cosmetics of the turn signal stalks from the first year or so to the 1973 stalks, with them changing to their final form with the '74 models? Similar with the underhood transducers. Slightly different cosmetics (especially on the transducers) but the same functions. I might be incorrect, but I consider them all to be "Dana/Perfect Circle" units. Perhaps I'm using "modern" terminology as Dana and Perfect Circle later became one company? And now Spicer is in that mix, too? The aftermarket units I saw from Perfect Circle, circa 1975, looked almost identical to what the OEM Chrysler units were.
As a point of interest, where did "Rostra" come into play?
CBODY67