Yes, that one won't fly, your prototype has 4 small fans. Either a GP7 or GP9 hood would work, most people wouldn't be able to tell the difference unless they counted the louvers on the sides of the hood. You can try Fleabay for a Front Range, Life Like, or Atlas Geep shell in the configuration you will need for your project.
BTW, RSO/ATest was a prior incarnation of Mehano, made in Yugoslavia.