From looking at the version "A" photo, it appears the one op-amp is used per string to both amplify the signal and create the hex fuzz sound.
If you look at IC6, at the top of the version "B" and "C" card, you can see resistors just to the left of the chip creating gain in the negative feedback loop, and additional diodes just to the right side of the chip for generating fuzz. After years of working with Roland vintage electronics, I finally noticed that there were two variations on the familiar hex pickup.
There is another reason why the G-303 is so popular: it is just a really great guitar.
If there is one guitar that has become the "gold standard" of guitar synthesizers, it has to be the Roland G-303 guitar.
No doubt much of the popularity of the G-303 comes from Pat Metheny, who has played this guitar year after year on stages across the world, always amazing audiences with the moving and emotional quality of the G-303 and GR-300 rig.
According to the schematic, these resistors should be 10K, but in this rare G-707 circuit board, the resistors were only 1K.
This 10:1 ratio difference is in keeping with all the other changes.
The pin out information was correct on the G-505 Service Manual Schematics schematic, which uses almost the same circuits.