I think it's just more of putting down a deposit to have your name higher up on the waiting list and then finalizing the options once the trim and color list is out. May or may not be a smart move depending on how many the dealership is allocated, buyer could be waiting for a while. Also, not sure if the deposit is refundable in case someone changes their mind.
Dealers are free to handle allocations however they see fit. Some dealers will take deposits, other may not (just have a list). If someone plays golf with the owner of the dealership, they could get moved to the top of the list at any time. The owner of the Honda dealer where I got my Fit EV took the first one the dealer was allocated - I waited 7 months to get mine. Honda never had a "master" waiting list for the Fit EV, I was on the waiting list at 5 dealers (none of them required/took deposits).
Honda said that franchise laws prevented them from dictating who the dealers delivered their allocated cars to - and this is for a car that is always owned by Honda (it is insured as an American Honda Fleet Car). I would expect that to be the case with GM as well - they allocate cars to dealers - dealers allocate cars to customers.
It would be nice to see what colors will be available both exterior and interior and the trim packages. GM should put this out there to get an idea what the public would be interested in. If I purchase the Bolt, you can bet I'm only buying one with all the options that I want, not what is on the lot.
We'll see what GM decides to do re trims/options. The Spark EV has just two trim levels (1LT & 2LT) and just ONE option (DC Quick Charge package). There is one paint with an up charge and then there are accessories (sill plates, wheel lug nuts, etc). I would expect to see more than that on the Bolt, but you may not have as many " a la carte" options as you might think.
The Volt also has two trim levels, but does have a handful of options (more on the "Premium" than the "LT" trim). I would expect to see something along these lines.
If you want one with very specific options like lighted cup holders, premium carpeted floor mats, illuminated sill plates, Driver Assist package 1 (but not 2), in black metallic with heated leather seats, you may have a long wait while the backlog is cleared on initial dealer orders/allocations.
I fully expect to see a roll out similar to the '16 (&'17) Volt - CA (& Canada?), then OR, other ZEV states, then nationwide.