At this time of year you are in the driver's seat. They don't want to store this one over the winter if they can make a profit on it. Do not be afraid to walk out if things aren't going your way. They will make sure to get your contact info before that happens. When they get you into the little room, be sure to tell them that you don't want to waste a lot of time there as you have another different unit to look at down the road at a competitor. That little lie gives them motivation. I wouldn't waste time asking for cards that may or may not tell you what they paid for it. That number becomes very convoluted when talking a used trade-in. They may have allowed a lot for the trade-in and gone skinny on the new one, or vice versa. What matters to you is what you are comfortable paying for your new rig given the knowledge you have picked up here.
Just remember that you are going in to buy an RV, not make a new friend. You can be friendly even when they start pulling their tricks. When you are in control and go in with knowledge, it is kind of fun to watch them fall all over themselves. Enjoy the process.
The bottom line is that they won't make a deal if they can't make a profit. You have to be willing to walk away. Many, many times I get a call asking me to come back before I even get home. It is then that I make them agree to my terms before I will set foot on the lot again.