I repainted mine a few times, you may have seen it here,
http://classicbroncos.com/forums/showthread.php?t=98590.
The rivets in the back are easy to drill, only drill as mush as you need to to get them loose. Once the horses are out of the way mask off the outer edges of the frame and the top of the B, trim it close with a fresh razor or Xacto but don't worry about the sport letters. Paint it with a light coat of color.
Repainting Emblems by
willtel, on Flickr
Once you unmask it you can take care of the letters and any bleeding around the edges. At this stage the paint should still be tacky, don't wait until it cures.
IMG_2819 by
willtel, on Flickr
Clean up the edges and the raised part of the letters with a cotton swab with some thinner on it. Go slow and don't use too much thinner, if it pools up anywhere on the paint it can cloud the finish. Once you have everything clean put the horse back on. I just filled the hole left by the rivet with some gel super glue. (I think these horses would make cool key-chains)
Bronco Sport Emblem by
willtel, on Flickr