I'm fond of the silver oxide as well, but a gold-toned brass would be the proper, classic match-up for a classically cut deep navy blazer. Could you provide more information on the blazer itself? A photo would be great.
Here's a picture of the blazer that I found (J. Crew Ludlow)
I'm leaning towards the silver oxide and dark matte at this point. The gold and regular silver buttons, although are very traditional, just seem a little too flashy/ostentatious for me.
myke