The rules state you do not have to spend resources (officials, workers) when receiving a governor or palace reward. Do you have to have those resources even if you don't spend them? For example, can you install a governor in a region that has no officials or a palace in a region that doesn't have two workers?
Official answer here. Keep in mind that other rules still apply. In particular, for the palace reward in the last round, you may not build a palace in a region with too much unrest. Also, the governor reward will remove all unrest as usual.