Sea Ray and several other manufacturers have introduced this type of pricing, generally on their entry level or "value" boats.
It really is just a pre-published price for a complete package (boat, engine, trailer, a few popular options, dealer prep, etc). No matter what price is shown or what options you add when you build the boat online, you'll still negotiate with your dealer to get the best possible price. It's just like buying a car. The price shown on the window sticker, website, etc. is just a starting point for the negotiations.