Good camera work and blow ups by you folks, I'm beginning to see everyone's opinion in the pictures, I guess it's like reading clouds. A physical inspection should tell the truth, even looking in the vent hole as mentioned or getting a hand on it. If it is where 2 metal liners meet then rust can create between them and actually separate them slightly (think threshold pinch weld).
Danny, what does the guy claim and based on what. Will he allow for a physical inspection by you or a third party. There are people who inspect cars for a living and yes some are bozos ( no offense to clowns) but what a little research and references you should be able to get someone qualified if you aren't comfortable doing it yourself.