Do you haggle when you buy a new (to you) car and trade in your old? Or do you pay full window sticker price?
I am not trying to be a smartalic here... so people do / some don't. I always have on vehicles but that was about it. Then I had a Boss who haggled on EVERYTHING he taught me well... jewelry, chain saws, mowers, I even got 10% off the Weber Grill I bought for the camper because I asked! All have wiggle room and most people nowadays look at the price tag and just fork over the money without even trying. I blame the big box stores mentality. Clerks can't budge there, but if you go to a local retailer he sets his price and profit margin so he can decide to take a little less.
I would not take the first offer... work him, I would even suggest to low-ball him... He will come back with a counter offer. If not, at least you tried.
TT: 2005 Coachmen 248TBG "Spirit of America"
TV: 2013 Ford F150 S/Cab 4X4