I'm doing a Brembo conversion and wanted to know whether I needed any washers for the caliper mounting bolts?

The calipers that I got did not come with any hardware. I managed to buy new OEM mounting bolts (#901120103) from the Subaru dealer, but the parts guy there said I don't need washers. However I've seen pics that shows a washer being used on the mounting bolts. So I'm confused

Also, I've seen some pics where there's some kind of black "brace" which attaches to the back of the caliper mounting points. I don't have it.....is it a required part to complete the conversion job?