It would be safe if the following conditions are met: it has reached an internal temperature of at least 145* (minimum safe temp per USDA for pork) prior to stopping the cooking to chill. Also, follow the guideline for non-intact meats if it has been injected, deboned or otherwise punctured (40-140*/4hrs). When reheated, USDA recommends a minimum of 165* internal temp (treat it as leftovers)...for pulled pork you would obviously be exceeding that temperature, so a non-issue in that case.
I would advise that the meat may become much more dried-out from the reheating. If it were at all possible to finish cooking on site would be best (any oven, or indirect on a grill), as this would reduce your number of the application of heat from 3 to 2.
Also, a better option provided there would be someone at home, run your smoke then go directly to the oven set @ 210* or so for a slow finish until you returned that evening, instead of smoking, chilling, then cooking to finished temp later.
Eric