Seat belts to chassis plates in rear wheel arch

[RayTVR]

Might be a daft question but;

I've got one with the bolt head in the wheel arch (which seems logical) but on the other side the bolt is through the seat belt so the nut and protruding bolt go into the rear wheel arch.

Is there a right and wrong or any reason for this?

(They're out for a bit of chassis touch up)