Not necessarily, since my father bought a 1967 Coronet 440 back in the 1970's that had a 318 c.i.d. engine.

http://www.allpar.com/cars/dodge/coronet.html

One of the two 1970 Dodge Station wagons my father bought later on in the '70 had a six-cylinder engine, but I don't know if it was the Coronet Deluxe, or Coronet 440. Incidentally, he was driving one of them during the 2nd Blizzard of 1978 and had to leave it on New York State Route 110 and sleep overnight in a bank building. The car ended up on the front cover of Newsday the next day.