I would tell them you are not paying for the pdi (predelivery inspection), this is something they are expected to do by FR and your aren't paying extra for it. Either you stick to the agreed upon price or you walk. Also do not hand over any money or sign final paperwork until after your walkthrough the day you take it home. You want to be certain the unit is up to expectations and anything g you find wrong should be fixed prior to taking possession, even if it means walking away. If it opens/closes, turns on off etc you want it demonstrated and you return the demo. Even go so far as to make sure the microwave is able to boil a cup of water (I had one run but not heat). Check for any trim issues, caulking issues, anything that could be wrong. Remember as long as you hold the check, you have the power.
2014 Crew Cab Chevy Silverado 3500 4wd Duramax/Allison
2014 Sabre 34REQS-6