Technically you could add the 2 coil 1938 regulator to your ‘37 system. The regulator would replace the cutout that sits on top of the generator. It would better control the voltage in the system to reduce the energy going to the battery.
Gene is correct that this change will not increase the amperage output of your 1937 generator. Generator output is a function of the amount of wire (windings) in the armature and field coils. Plus there has to be enough air flow to keep the generator cool.
You could adjust the third brush position on your 1937 generator to produce current well above the 18 amps that is is rated to produce. Except it would not do that for long. The most likely failure would be that the armature would get so hot that the solder between the windings and the commutator would melt.
. The standard generator for 1937 Chevys was the 3 brush, 17 Amp generator with a cut out and no voltage regulator. If you had Radio, Heater and the headlights on at night, you would quickly have a dead battery. Chevy offered many upgrade options. One of which was a 12 volt alternator. (See first photo). Because Diodes had not been invented, rectifier plates were used. One of my 37 Chevys has a 6 volt alternator and 2 six volt batteries in parallel. With grille removed, you can see the rectifier plates and three wire regulator in second photo. . Lou . .
Current regulator only operates when battery has low volts due to a run down condition to protect the armature. In normal use with a charged battery it does not function. Only the voltage regulator functions to keep the voltage at a preset value around 7.3 volts. The 3 brush generators maximum current was set by the position of the third brush. The manual states not more than 2 commutator bars between the negative brush and the third brush. That setting takes care of the maximum charging current for 3 brush generators.