I've bought very few new guns, so when I'm looking I'm always in the mindset that the gun I'm holding in my hand at that moment is the one I would be taking home if I decided to buy it.
It always sort of catches me off-guard when I buy a new gun and the clerk tells me that they need to grab another one from the back to sell to me. I'm always happy when they do, but I certainly don't expect it.