You can save a nice bit of money if you negotiate for the basic trailer and then after the deal is settled work on add-ons, which could include the AC, awnings, shore power cords, etc. and try to get these at the dealer's cost.
Most dealers do not want to lose a sale at this point of the process and you are heading into the winter when RV salse will drop, and the profit on the RV is what they need. The extras are not a big deal and the dealer does recover their costs. I got a 66% discount on the list price for a new AC unit this way with my last purchase.