One really easy, quick and reallistic way to do scale rivets is to use the Pro-Mark dry transfer rivets.
You just cut rivet strips from the sheet and apply them on the surface before painting.
After painting you will just need to sand the paint slightly away with a fine grade 3M sanding pad to get the effect you want.

Always remind that a rivet is not a hole in the surface but a "o" shaped mark...



Pro-Mark make rivets sheets and screws sheets ( here shown around on the alpha vane )
http://www.pro-mark.com/rivetslg.htm
http://www.pro-mark.com/screws.htm