A very early Embo chassis by the look of the squared off rear inner fenders, is the VIN# an 8XXX or 9XXX? Should have the lower floor pans and extra headroom. They were all sold as either GTS, GT5 or GT5S at that point, but again the only cars to bear 'GT' in the VIN were the 150 US specific GTS package cars.
Aussie Cleveland's were not introduced until the mid to late 80's.