I use the stamps for the background just as TwinOaks suggested. I stamp, turn the tool, stamp again while overlapping and continue this way. I have found many Firefighter's perfer the textured look on thier fire helmet shields.
For the first holster, I don't mask off anything. I really should I guess but i just use various detail brushes AFTER I use the antique technique. The second holster is exactley how TwinOaks stated.