It is probably that there was once a kit that included Hornet M1 at the rank of Warrant Officer 1. And then he might have been away from tanki online and now since he's back, his tank is different from the rest and it is not even possible to have it again. Just think of a possible solution, it's not like he hacked to get a modified tank at that rank, it's not possible to from what I know.

I thought I was imaginating when I saw the Easter egg XD