There are new dog tags that came with the DLC's. But the most recent dog tags are not just given to anyone. ONLY
Premium members can get there hands on the Black Dog Tags
I'm using the "Jack of all trade" dog tag -
In order to get this tag, you must unlock the other premium dog tags, then complete the assignment for the tag. A total of 5 assignments. The only tag you don't need to unlock is the Battlefield Premium dog tag which is given to the user for becoming a premium member. All other Premium Dog Tags must be unlocked by completing assignments.