Extension springs on tracks
That gap matters on a garage door call. Doors and openers from the mid-1970s were commonly set up with extension springs running along the horizontal track rather than a torsion bar over the header - a setup that's cheaper to fix but far less forgiving if a spring lets go near the door's edge. We still carry parts for that generation of hardware, but it's not the stock we move fastest, since most of the broader area skews newer.