Keihin 22mm carb - washer question

Included in the Honda gasket kit for my XL100's carb are a 6mm metal washer, a red fiber washer, and a small o-ring. Can anyone tell me where the metal washer belongs? I can't find it on the parts fiche. I'm assuming the red fiber washer goes under the float valve, and the o-ring belongs on the drain screw. Thanks!

Looks like the washer on vacuum plug but 100 didn't have a vacuum take off
Maybe it is for vacuum barb if you had a very very late model which had a vacuum fuel tap

Thanks so much! Unaccounted fasteners keep me up at night, but since my XL is a '74 I'll sleep like a baby tonight.

Same thing with my CB100. I think the rebuild kit spans a number of years and models, so just go by your specific year's parts fiche and you should be good to go. Sleep easy!