There is a bit of controversy over the exact color of the web pistol belts. As typical it all goes back to "Different colors appear on screen in different ways according to the lighting and materials."
The general consensus over at BlackStar Squardon (A BSG costuming site) is that while the belts appear blue in many scenes or photos, they were likely not actually blue USAF web belts. There is also supposedly an interview with the costume designer where he said, "I'd never use blue belts with a brown uniform." (Although I've yet to see that actual interview myself. I've only seen people reference it).
The guys over at Black Star have had good luck replicating the look of the web belts by dying white web belts black or even taking standard olive drab web belts (as most military surplus belts are), stripping the color out with a dye remover, and then dying them black afterwards.
This results in a sort of gun metal gray that can even look blue-ish under the right lights.