I can't be sure of the exact answer to your question, but I just picked up our vouchers for the military salute tickets at our base ITT office yesterday. It is those vouchers we take to a guest services window or turnstyle to actually get our tickets. So I'm sure we could get the tickets using the vouchers, but not enter the turnstyle (Which is what you would be doing the night before).
In fact, we will be arriving early afternoon after a flight from Ohio, and three of us will be using tickets that afternoon and evening, but the fourth person in our party will not be arriving in the parks until the next day. We were told we could pick up all 4 tickets (my DH, the military retiree, will be with us), and just not use hers at the turnstyle until she arrives the next day.