Copper washer in Fuel Line ?

[gidpor]

Hi,
I began replacing the flexible hoses(dry,hard & full of cracks) coming out of the bottom of the Fuel tank. I began by removing the Fuel pump/filter/accumulator as one piece - and then undid the flexible lines & removed the fuel tank filter ( Actually, it was not at all dirty) . All went well but when I finished taking things apart, I found an unaccountable copper washer in my lap...the same kind and size we all use for the oil pan plug. I am trying to figure out where this washer came from ?
I can only think of the smaller line coming out of the tank # 126 470 4175. Can any one confirm this ?
I am posting a few pictures. Before as well as what I think should be. Also , is the orientation of the "unusual Perforated washer" correct ?

1987 300SE -126