You already have the PR-2, correct? If so you should be able to test this yourself by switching Output Setting to LTC-3V, starting a recording and listening for time code out of the 1/8" monitor output, or just route that output to another recorder, adjust gain and visually check for time code signal on its meters.
If that works, then play with either 'Y'ing the LTC to both DR-680 and camera, or chaining to camera through the DR-680