Does the dealership have any reputation sourced from friends?
If you added the 2 quarts, was there any improvement in operation?
I ask because a friend bought a '97 F-150 4.6 from a widow. The truck had sat for >2 years and it went to a friend's garage for some "pre-delivery repairs". The bottom line here was that it was owned by my friend for 10 weeks but driven for only 3 weeks lacking 3 quarts of oil. The 4.6 takes 6.
After adding the needed oil he said the difference in smoothness and pedal response was huge. In fact, it was the clattering the engine did going up my hill which prompted me to check the oil at the very next stop.
It's 6 years and 35K later and the engine runs strong. It's not a tough call you're to make. It's a guess.
I wouldn't know what to make of all the "dealer let you take it home" stuff. I thought that was to get people with budget limits to buy via peer pressure. "Hey Bill, where'd that nice truck go?", is one question many wouldn't want to answer.
Good luck.