Becky gives the cut-off dates in entry #3 in this thread:
http://www.camaro6.com/forums/showth...ighlight=order
There are a number of Camaros sitting on lots now. You could do an inventory search to see if the options you want are commonly available. If not then you might want to order. If you aren't in a hurry for a car then you could wait and see what deals are available over the next few months and order a 2018 if you can't find the car you want.