Let me suggest a scenario that might just be true:
(1) You stroll into your local Toyota dealership, and you tell the salesman what you are interested in buying.
(2) The dealer, knowing he has nothing close to what you want, does an area or nationwide search.
(3) Finding THE EXACT "UNIT" that you want in Crick Holler, WV, he contacts the dealer in Crick Holler to say he may have a buyer interested in a Tundra just exactly like the one he has in stock.
(4) The dealer in Crick Holler, WV says," Yeah, I would be interested in $$$ - $$$$ over cost to me."
(5) Your local dealership comes back to you and says, "Yes, we have found the one Tundra that you are interested in at another dealer, and pending a signed deal, we can have it here for you day after tomorrow."
(6) Now the sticky part has to happen without any tangible evidence of your dream truck actually being IN EXISTENCE...getting your autograph on the paper.
(7) Once the deal is signed, your local dealer calls the dealer in Crick Holler, WV, finalizes the deal based on how much he's made off you, and tells him to send it. Now, if some hill hopper comes in and BUYS your dream truck while you were dithering, then your dealer gets told "Sorry, no longer available". THEN, your dealer can't deliver the deal he promised you, and everything is null and void...unless you are stupid enough to wait. You get to start over again.
(8) Dealers do this exchanging of "units" all the time, and have a good handle on what an "exchange" is worth. They may even receive guidance from corporate on reasonable "exchange" prices. If your local dealer can make what he wants out of the deal INCLUDING the "exchange" price, then everyone is happy. Right??!!
Just a little additional info..."units" are seldom driven to the dealer receiving the "exchange". In my experience, they are typically "flat bedded" to the receiving dealer as part of the "exchange" price. There will no clue where this vehicle came from based on mileage...it will be the same as it was in Crick Holler, WV.