I just spent an hour looking at the mustang in person. I believe it to be a real K code. Per the photos on the listing the engine appears to be correct and it appears to have the correct valve covers and a dual point distributor. The engine has the wrong intake, carb, and no air cleaner. The AC and power steering are from 67 or later judging by the brackets, clutch and pump used. Owner says the tag on the steering box is correct but I couldn’t make out the numbers. Also I don’t believe the car is a factory GT or a factory deluxe interior car as the dash does not have the dip for the 5-gage gage cluster. The ammeter is correct for 65 not the 66 version. I did not get a good look at the wiring harness to see if it’s a 65 or 66 harness. The rally pac is for a 66 not a 65 and it did not have a ford engineering number. The drivers floor pan has been changed and the fenders and quarter have rust in the typical places. Rear floor pan and frame rails need replaced. Truck and engine bay look good. Engine runs pretty well for its condition. I’m still very skeptical on the door tag. The font and centering of the numbers doesn’t look right but the rivets are correct. Only 3 style steel wheels, 1 Shelby style wheel.
Would be curious to know what others think of the door tag and GT/ deluxe interior options. Owner will not budge on price nor is he willing to accept that the AC, power steering were added later in life and that the car may not be a GT or deluxe interior car from the factory. My theory is that someone added these options and had a door tag made to match the interior change etc.