Jeff, thanks for chiming in here. I stand corrected. Your kit number for an FS90 is not the same as I posted above, but my purchase was several years ago. And, yes, it did not only have the feeler gauge, but also the two gaskets you noted. The larger one can be seen in the package.
As for price, I do remember the larger price paid at the time, but I bought other things at the time. I went back to my QuickBooks records, and found that I had not only the kit, but some other things. So, I was wrong about the price of the kit, but right about having paid more at the time because of buying more things. Thanks for clearing. I still do find the $0.20 interesting for any Stihl part, but will defer to your familiarity. Somehow $0.20 and Stihl don't go in the same sentence.