Mid-century hardware era
That's not surprising once you look at when these houses went up. San Mateo's housing stock centers on 1964, right in the middle of the wider service area's 1947-1987 build window. Doors from that era were built with hardware that was standard for the time - heavier steel panels, extension springs mounted along the horizontal track instead of a torsion bar overhead, and simple roller-and-track setups with none of the sealing or balance adjustment built into later systems.