Who knows with dealers! I just received a letter from my dealer; they want to buy my 2013 Ram 1500 from me for what I owe, plus enough for me to buy a 2015 with the same monthly payment.
Could be the dealer you are working with just doesn't want your model / year truck right now... if you have a better deal in a private sale, go for it... or let your fingers do the walking and try a few other dealers... you're not limited to your home town, or home state even if the deal is good enough on the new ride.
Shop around on this first time co/sign business too - sounds like B/S.