It's no coincidence that the story was picked up after the recent shooting in Colorado. The media is becoming a mouthpiece for foment on guns, gun ownership, gun rights, etc.
Also, as far as I can tell, none of the superlatives being applied to Mike's lower are actually from Mike's mouth. I don't think Mike is claiming that his 3D printed lower is the first one ever made. The news articles, however, are applying that title. It may be the first one that the authors have heard about or seen, mostly because of Mike's desire to be fairly open and share about the things he does/discovers.
Most other people are fairly secretive about these types of things for obvious reasons.