I checked the project and R20 is a generic 500 Ω, 0603 resistor, not a manufacturer-specific part.

I could not find an exact datasheet for R20, because it does not have an MPN assigned. The web results only turned up generic 0603 chip resistor families, not a datasheet for this exact placed part.

Because R20 is a generic part with no exact datasheet, I can’t accurately give datasheet-derived:

For a generic resistor, the two terminals are typically interchangeable, but I’m not going to present that as a datasheet fact unless we first assign a real manufacturer part.

I can help you:

If you want, I can next find a suitable real replacement part for R20 and give you the proper datasheet-based breakdown.