Yah, look at the head of the bolts and replace with whatever was originally used. FWIW, I've got twice as many bolts on my KLR, and that might mean something (like, for example, that there's more stress on that attachment than you might suspect), which in itself suggests erring on the side of more thorough rather than less.
I'd answer differently if you were somewhere in the middle of nowhere in the Developing World....but you're not, right? Do you really want to ride that bike around all over the back of beyond wondering whether the strange new vibration you're feeling is related to using junk bolts on your rear sprocket? I didn't think so.
Mark
(from somewhere in the middle of noplace in particular, Bahia, Brazil)
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