weird Fender Tag space on 70 darts

so, i'm getting my fender tag remade as it was lost...but i'm confused by a space on several 70 darts in the 3rd line. This is just a pic of an example....but i found several with just a google image search and they all had the space. is this just a Dart thing? i saw some duster ones that did not have the space.

can someone explain?