I normally don't work on gas engines beside my hobby cars, but that sounds shady to me. I may be wrong but the compression on a cylinder is eather bad or good. I never herd of a leaking hole in the cylinder.
A bad head gasket would give you bad compression but you would also have coolant in your oil (grey oil), there may be leaks along the side of your engine block and many other symptoms that are associated with that problem. Your best bet is to go with Rod's advice. That is the fast, easy, and inexpencive way to find the problem. Sounds like that dealer is trying to take you to the cleaners.