No-one that I know knows where the original Ewe't is now, or the other 350 Kingswood ute built 2 months later. That magazine article actually has a mistake as it states the car has a LSD but it only had air and steer. The second one was steer and LSD. Those wheels were firstly on the 350Z, then on the HQ Premier styling car for the SS and left GMH on the Ewe't. They actually became a HJ option not long after (option PE1).
Sandman was a sports package, not an engine option. Plus the 350 was all but obsolete by the time the Sandman was released and for the whole time Sandman existed it was available with the biggest engine available with a manual transmission - the 308. By that time the 350 was basically auto only. Leo Pruneau wanted the quad nose for the GTS from day one, and if the GTS got it Sandman would have got it. He wasn't allowed to have it until HZ!