joshua... I believe some smaller agencies may use Cor Bon, but I know of no major agency at the State or Federal level that uses it. There have been QI problems with Cor-Bon in the past. They have tended to switch components without notice. Perhaps they're better about it now. Most agencies get volume deals from the big ammo manufacturers, either on their own or buying through a co-op effort with neighboring agencies or State agencies, so pricing isn't the issue it might have been in the past. The market is pretty competitive regardless.
texaseyes... the so-called 'daughter particles' of a frangible round like the Glaser or MagSafe round can indeed be traced to the manufacturer by various means, and the jacket or cup that holds the particles will bear rifling marks which may or may not be forensically useful depending on integrity of the jacket when recovered from tissue.