Rebuilding my 1979 308gt4 Water pump

I have a 1979 308gt4 large bearing water pump.
This link was a great help, Thanks Carl:
http://www.r-design.net/308/index_e.html

When I dissembled my water pump, the flat ceramic washer and spring seal part fell off the shaft prior to me being able to determine their orientation and sequence.

I’m receiving differing information on where the flat ceramic washer goes.
I’ve been told it goes into the back of the impeller, ceramic side facing the pump (My Impeller has a recessed area that the flat ceramic washer fits into perfectly)

I’ve also been told that this flat ceramic washer fits into the pump housing next to the back bearing, ceramic side facing the impeller with the spring seal fitting over this piece.
As shown in the diagram located at:
http://www.ferrparts.com/part_index.php?Veh=308_GT4_Dino_(1979)&Tav=16

I’ve placed a few photos of my old spring seal so you can see what version I have.
I’ve been told this is Ferrari part # 100433 and awaiting shipment of these parts as we speak as we speak.
Can you shed any addition clarity in this area?
I appreciate your help on this.
Steve
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