Patrick Duffy's son Padraic Duffy plays a character named Mark Harris. This was the same name as the elder Duffy's character in Man from Atlantis (1977).
According to his passport, Bobby Ewing was born on February 16, 1950. However this contradicts earlier episodes where his year of birth was given as 1949.
April Stevens Ewing was born on August 7, 1957.