I had a chat with a SA in a showroom today and there is an unwritten rule that seems to suggest orders are prioritised as follows (from memory)
1. Cash + EAP/FSD
2. Cash standard AP
3. Finance/Lease + EAP/FSD
4. Finance/Lease standard AP
Seems in general terms, lease customers are prioritised last, especially if you didn't order FSD or EAP.
I am sure that they probably match customers by week number too. So if you are 1 or 2 customer (as above), you can probably get matched sooner despite ordering 2 weeks, maybe even 4 weeks after a lease customer of the same spec. That certainly happened to me.
This is all conjecture and second hand info from a sales advisor. It does seem plausible.