When we factory ordered our current 5th, we specified we did not want the fireplace, nor did we want the wall mounted grill outside...no problem. What we got instead of the fireplace is a decent size storage cabinet. Didn't like the look of the fireplace...sure some say they get enough heat from it to take the chill out on some mornings....we use an electric heater if ever that is needed, or simply run the furnace for a few minutes. And to be honest...I forget how much we got as far as a credit for not taking the fireplace.
As for the outside grill...they still ran the propane line to the outside wall and put the bracket to hold up the grill, we just didn't get the grill. So if we choose to have the grill there in the future we could always do it, but I don't see that happening.
2011 GMC Sierra 2500HD
2014 Rockwood 8289WS, Diamond Pkg.