Not sure I follow. I don't care if it's literally the only one in the world or something with 50 million currently in use, I'm not buying anything until it passes some sort of basic inspection even if only reviewing cosmetics. I can't imagine a seller insisting otherwise. After you meet to see the item, if it is not to your liking for the price agreed to, simply don't buy it. What am I missing here?
I have had several sellers (over years) that refuse to allow an inspection of the firearm before receiving an offer to purchase. Their responses make reference to "tire kickers" and "lookie lou" who their busy life does not allow them to deal with. I'm talking about $1500 guns and up.
Keeping in mind the expansive definition of "95%" condition that seems prevalent on ODT.
The attitude seems unique to the gun sellers, as I've bought stuff from nearly every other listing, and everyone else is comfortable with "I'd like to look at before I commit to buying it".