My understanding is once it is a special order the DSO is irrelevent to the sales area and only references the special order.
Forest service, construction companies, etc. can get special builds to this day. I think the current standard is you have to buy at least 10 of them. At which point you can have them built in non-standard combinations as well. King Ranch with vinyl floor painted purple? Buy 100 of them and I bet they will do it. My understanding (of current practice) is they build the first one, the buyer signs off it is correct, they get the rest of the batch made.
This is very much like how the Twister Special Mustangs and Torinos were built in '70. They were made for a race series as a special order but the series went bankrupt before delivery. They got turned into a special series for the Kansas City dealers.