So Tony as for fan mounts are you allowed to mount a side motor fan like this for Formula E?

This guy looks to have drilled into the side of the chassis to screw it on and also just screwed on a top empty hole. From what I interpret from the rules, that wouldn’t be legal right? (Though its actually quite clever and i’m baffled its not like that in the standard kit)
I was planning on buying a tamiya brand motor fan mount, but looks like everyone is sold out. Is a non tamiya fan mount legal to use?