Hey Bill, I saw the white/red pair a lot in old 25 pair pole terminals with lead stubs when doing splice repairs. I have seen a white/red AND a white/black spare pair in T-screened OSP cable recently, in fact we just installed about a mile of it.
I also still see this pair in some of the really old, as in 1950-1965 inside cable where it was available in brown or beige jacket and solid colors like PIC.
I am pretty sure that once band marking for pair identification became the norm in the mid 1960's for inside wiring, the spare pair went away.
