I think you're not in terrible shape. Among the 8 different area dealers I shopped before pulling the trigger back in Sept., FWP was the norm. I did however put down a deposit and got a signed Buyer's Order for the FWP at the time, not a penny more. Now per my window sticker, MSRP has gone up $685 (roughly split between Rebel base price increase and Level 2 package increase), which means the dealer is going to eat the increase (or else!

). Without the signed Buyer's Order, yes they can try to pass an increase on to you, but you always have the ability to negotiate/raise hell, or walk.
If you put down a deposit, then your order should qualify for Sold Order Protection. That means you're eligible for whatever incentives/financing deals apply to your truck *at the time of delivery*. The dealer cannot deny you those benefits, they're from RAM. So while it's true that they don't know what your "out the door" price would be, since RAM incentives/financing change every month, they surely could've told you what your out the door FWP price would be, less those (unknown) incentives. The signed Buyer's Order is the tool that locks that down.
I'm satisfied to get the Sept. FWP. I thought about Mark Dodge but they're far from me, didn't feel like the added cost/hassle of getting the truck back home, and wanted to build a relationship with this local dealer for their added perks and service.
Good luck!