Nope, you would do your online check-in (earlier than a first timer) and pick a port arrival time. Your PAT will determine your boarding number (earlier PAT, lower boarding number).
So, Concierge/handicapped first, then boarding Group 1 (Platinum), then group 2, 3, 4, etc. Silver could have a boarding group 2 if they have a very early PAT available at online check in.
MJ