I'm pretty sure the JC-120 creates its chorus effect by running an unaltered signal via one speaker alongside an altered signal via the other speaker, so if I were to mic the amp up close would I need two mics recording in stereo (one mic for each speaker) to properly capture the chorus effect?
I can't verify how the JC-120 chorus effect works, but if that is the case and you want to capture the stereo chorus effect, then short answer, yes.