A lot of American (and old American) personal names and words in general are old (as opposed to Old) English words which have died out on this side of the Atlantic. Usually revived by C&W fans and others!
Gulliver's (of Travels fame) was called Lemuel and the name was revived by Charles Chilton in the 50's, calling his Cockney Journey in Space character Lemmy Barnet.
A lot of forenames were originally surnames, like Hamilton - a common enough practice and Alton is an occasional surname I've come across.
Incidentally The Oxford Guide to first names does not list Rabon (could come from the English surname Rabourne, a place name) or Lavon (seems to come from a Russian surname variation)so these must be very rare. It does however list Alton as a forename; it was Glenn Miller's first name by the way.