I visited the plant last Tuesday and observed that the assembly line not only contains vettes of different colors, but also contains coupes, convertibles and Z06's all mixed up in the line. I asked the tour guide the same question you asked and he told me ALL Corvettes are "made to order". He explained that 90% of them are made to "customer order" and the remaining 10% are made per "dealer stock order". I observed painted bumpers of all colors on the same rack. I also saw an orange Z06 being test driven. Hope this helps.