Chain Drive Opener Age
That decade-plus gap matters more than it sounds like it should. A house built in 1978 was far more likely to come with a chain-drive opener installed from new rather than retrofitted onto an older door, and the logic boards and safety-reversal wiring in that generation of opener are a different animal from what you'd find on a 1950s Charleston bungalow that had an opener bolted on decades later.
