Yes, at least if you reside in the US, they send them to you. Once your deadline for customizing arrives, they make them and send them out within a couple days, and you should get them a couple days after that. Right around 30 days.
If you don't reside in the US, they are sent to the resort for you to pick the up. If you have separate linked ticket media you _might_ be able to get in to the parks and use FP+ - otherwise you need to go to the resort first.
If you don't customize, or book a resort at the last minute, you will be given the "Iconic Gray" bands by default when you check in.