Earlier than promised, Rockstar has made available the free chrome guns bonus in Max Payne 3. Just restart your game and then head into the loadout menu and equip the chrome variation for your gun. All you need is to do is be a Social Club member. One cool perk to the chrome guns is that they give off a highly reflective glint, potentially distracting your enemy.
Additional special bonus upgrades are coming soon along with more information on the rest of the DLC packs.