What Jess says is the way to go. But, you can find good quality chrome metric hardware at some Ace Hardware stores.
I always take a OEM bolt with me to check the pitch on the different bolts, I find a nut that works on the OEM bolt and make sure it works on the ones I'm buying.
They have charts with the different sizes and pitches, but having one with me is easier.
Honda chrome quality is some of the best there is.

Great points. Do that myself. But most spacers anywhere on the bike only say
spacer or sleeve with a part number in the fiche (so I got 3 lengths, and one worked).
I agree on Honda chrome hardware. Sometimes I don't also agree with the price. And some stuff down low (prone to crud and wet) and pretty hidden is better stainless than chrome anyway.