Dating polytone amps
There is another reason why the G-303 is so popular: it is just a really great guitar.
There is no learning curve to the G-303, no time required to "get acquainted," this is a guitar you want to play as soon as you put your hands on it.
All the G-303s and G-808s that I have checked have op-amp pin outs consistent with the G-505.In addition, the standard 1/4” output jack solders directly to the PCB, rather than the ribbon connector.The first time I tried to repair a failed op-amp in a G-303, I realized that the pin-out documentation was wrong on the schematic.The other vintage controllers, the G-202 and G-505, are well-built, fine guitars.But they cannot escape the feel of being really well made Fender copies, no matter how nice they are. The more expensive G-808 has through-neck construction and other nice features, like gold hardware.