Many bikes come as a double or a triple. The LBS chooses whether to stock one or the other or both. Often the triple is about $50 more than the double. The "optional" description means the shop can order that bike as a triple. It is up to the LBS as to their policy for special order bikes. I know my shop will order any bike in for a customer. I have to have payment in full, and I have charged a 20% restocking fee if the order is cancelled. I explain this policy up front on doing the special order.