gaka? pfft! XD

This is very likely a mirror reflection, but the words aren't reflected in reverse... error tag maybe? Or the artist intentionally did it judging from his other works?

Since it's in English, that would be how you'd write it backwards in English.

I don't know why the artist is inconsistent about the reversal between the nametag and other callouts in his Lawson theme, but at least he's consistent in that inconsistency.

All the English text is written in reverse, so I'm pretty sure this is intentional.

GAKA, as well, would probably look more familiar to you if it were written in katakana as がか.

... Except the "Lawson" on Kaga's nametag is not reversed at all.