I buy my regular stainless and polished stainless fasteners from Totally Stainless. They have a very nice catalog that is year specific, as well as miscellaneous fasteners sold individually or in bulk, both polished and unpolished. I believe their catalog is free and a great source of factory correct stainless and OEM fasteners.
I also buy stainless fasteners from The Home Depot, Lowes, Ace Hardware and Fastenal. There are many good sources, in most metropolitan areas, as well as online. I also have a source in the Kansas City area, called Metal By The Foot. They have a wide assortment of all grades, shapes, sizes and finishes of fasteners. Check your local phone book for steel suppliers and they may carry a complete line of fasteners, as well.
Good luck with your search and I hope this information is helpful.
Tony