In dire need!!!

[Gs500_Rugger]

I was rebuilding and cleaning my carbs off my 93 GS when I found that one of the special o rings that sits under the white plastic slide guide is missing.

Is it really that important?

Regardless of the answer to that question, does anyone have one laying around they'd like to donate or sell to me?

PS. If any has both float needle seats with o rings, and/or bowl gaskets in decent condition, they'd be much appreciated as well.

Oh and if anyone could inform me of where each O-ring goes that is included in the following rebuild kit, that'd be awesome too:
http://www.ebay.com/itm/181280785676?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT