"Are you for real?" asks a caller to The Phil Hendrie Show. "You must be making this up." For Miamians who enjoyed Hendrie's satirical shtick during the two-and-a-half years he broadcast on WIOD-AM (610), the impressionist master's syndicated return this year on WINZ-AM (940) is the best thing to happen to Miami radio since he left, two years ago. Sure there are some changes. Stock characters such as steak house owner Ted Bell made the move west with him. Show-business columnist Margaret Gray no longer hails from Bal Harbour but from Pacific Palisades. (Recently she encouraged abortion as a way to generate fetal tissue that could be used to research a cure for the paralysis that cripples actor Christopher Reeve.) But like fans of a minor-league baseball team, those of us who heard Hendrie hone his act in Miami feel proud of his success and glad that he can now exploit an entire nation of gullible listeners, a never-ending supply of dupes questioning the credibility of, say, the recent guest who claimed to have invented solar power.