Late-1980s hardware differences
That matters more than it sounds like it should. A door and opener installed when a house went up in the late 1980s is a different animal than the one-piece doors and heavy torsion setups still hanging in houses built in the 1960s a few miles over. If your house is original, there's a decent chance the opener has been swapped once by now, but the springs, the hinges, and the track very often have not.
