I did work in a house that was built in 1909 and had the entire basement ceiling covered in T&G beadboard. All of the water lines and electric lines were surface mounted, the house had 4 or 5 bathrooms and the pipes ran all over the place with many of those fittings. The knob and tube wiring ran in wood tracks with a wood cover screwed on, at each splice/ intersection there was a wood box and the track would go off in a different direction. Really amazing to see.