That really depends on the dealership. Some are happy just to add it to the AP to pay when it’s ready, others want optional extras paid in full in advance. The only really accurate answer is to have the conversation with your dealer and see what they say. I’d frame it around making sure you’re properly prepared to put the order in, that may make it an easier conversation.
I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
I'll try to give my honest opinion but am always open to learning.
Mark