Replacing the power steering pump on a 4.0L -- use the washer?

[Tony-770]

Hi, I'm replacing the power steering pump on my 4.0L Ranger -- the old one doesn't work anymore. The pump on it is one of those with a separate fluid reservoir -- I'll attach a picture for clarification. I bought a rebuilt power steering pump for the swap and it comes with a small (about 1/2 inch) white hard plastic washer. The instructions with the pump basically just says to "use it if you need it", and I don't know if I need it! The Chilton book I have doesn't mention the washer and the Youtube videos I've seen on replacing the pump don't mention using the washer either. The only place I can find that the washer could physically fit would be inside the pump where you screw in the high pressure hose going from the pump down to the steering hardware. The washer is too small to go on the hose fitting, but is about the same size as the hole in the pump where the line screws in.

Does anyone know if I'm supposed to use this washer?