The best and most up to date info on this is going to be over on the Who Ordered a 2012
thread pinned to the top of the forum.
The only thing that will make a difference is your dealer's allocation and the Priority Number assigned to your car (especially important if multiple Mustang orders are in play at the dealership you ordered from). Commonly passed along info is there can only be one Priority 10 per dealership, this is not true. 10 is the lowest (best) priority a dealer can assign to your order upfront.
The final assembly for all Mustangs is at the Auto Alliance Plant in Flat Rock, MI, regardless of whether the car gets a manual (made in China) or the auto (made in Livonia, MI). Things may have changed, but the hold was on releasing cars from the plant, not building them. Yeah, doesn't make much sense to me either.
Here's my timeline if it helps, fairly typical I'd say IF your dealer has allocation, 15 days from order to VIN.
Placed a new order with a new dealer (Chapman Ford of Marysville, Ohio) on 04-01-2011 ● DORA 04-05-2011 ● Build Week Assigned 04-12-2011 ● 04-15-2011 VIN ● 04-21-2011 Window Sticker/Build Date Online ● Bucked 04-27-2011 ● Completed 05-02-2011 ● Arrived at dealer 05-26-2011 ● Took delivery on 05-27-2011
PS Not to scare you but it took me over 8 months all together because my first dealer screwed up my first order (a late 2011) then didn't have allocation to get a replacement. Some people have been waiting even longer. If you haven't heard anything yet, I'd sort of think you had an allocation issue. Did you contact Deysha?