First two ordered get cars... unless the dealer feels #3 is higher priority customer.
Dealers can be VERY VERY shady. When I ordered mine, I watched EVERYTHING he did. I know I was #12, I know what status the other 11 before me were at, I knew where they stood on allocations... all before I gave him a dime. My order went EXACTLY as he said it would. BUT there can be some real scum sucker desler's out there.
If you got one...

but say your number one and I go in and say hey dealer owner... I'll give you $20,000 over sticker for two ZL1s... what would he do??? The ethical dealer would say I'm sorry, they are sold. The scum would take the money, put them in as 1 and 2 and you'd be SOL.
Hopefully none stoop to that level but it could and has happened!