Oil leak after engine overheat

[dtb522]

Had my alternator changed along with serpentine belt and tensioner. Shop left upper coolant hose loose and engine overheated for about a minute or two, pegged all the way over. Stopped and it was towed back to shop where they corrected the situation and "checked everything over" giving the thumbs up. 5 days later I noticed an oil leak which this car has never had. Back to shop and told camshaft seals are leaking. Car has 120,000 miles. Shop says normal wear for cause of camshaft seal leaks and that sounds reasonable to me except it started after the overheat. Could the engine overheat have caused this problem? Shop says no, that it's just coincedence. Any thoughts? I doubt I can prove the overheat caused the camshaft seal leak what with the car having so many miles. I don't have any obvious symptoms of a warped head but maybe I don't know what I'm looking for.