Silly question....

[Timo]

Originally Posted by jasedee

(Q) Should the Left channel on the Mackie console (whose feed is from the Left output of my DJ mixer) be panned hard left? (And the same for the Right channel)

Yup, absolutely.

The reason you might have been unsure is due to another, different panorama-based control called "balance" (instead of "pan"), which affects a single stereo image rather than two x mono L/R channels. Most channels on mixing desks (as opposed to DJ decks) are mono, therefore need to be 'panned' in order to actually create a stereo image.
Otherwise, for 1 x stereo inputs you would generally leave the 'balance' midway, as 0, and thus the original stereo image is retained.