an unconditional three day inspection period is a two edged sword...

yes, it gives the buyer last right of refusal after receiving the item.

however, it leaves the seller vurnable to tire kickers, thieves and in the case of internet transactions, the possibilty that the receiving dealer will convince the buyer that he is better off buying a better gun from him...

best return policy is this:

"Returns are handled on an individual basis. You can expect that I know what I am selling. You are expected to know what you are buying. All items are guaranteed to be as advertised. If I make a gross error in description, you may of course, return item with my apology"

this way, both seller and buyer are responsible. and it heads off the competitive receiving dealer.

keep it simple and keep it safe...