1939 was the last year for a cutout. In the initial part of the production run (1939 models) the Standard did indeed get a cutout while the Deluxe got a regulator. Around February, 1939, all models, Standard and Deluxe were supposed to have a regulator installed. How quickly that actually took effect is anyone's guess. Probably within a few weeks...
Note that the generator was specific to a regulator OR a cutout. the two could not be interchanged.
There is speculation that throughout the entire production ruin, the Standard, when ordered with a radio, got the voltage regulator. I can't say how true that is.