To the best of my knowledge Verizon does not buy refurbished or used equipment. However when equipment breaks or customers cancel service, the equipment comes back in, is checked out and/or repaired as necessary, and then goes out to customers again. These things are simply too expensive to toss out unless they have reached end of life, or are not economically repairable.
It is a safe bet that any customer getting a 6416 DVR is getting one that has seen a good deal of prior service, and at this point I doubt there are any new 7216's in inventory. If you are gettinga Cisco or 7232, odds are you are getting new equipment, otherwise it is almost certainly refurbished/repaired by Verizon after being returned from a customer.