Eric (turbofish) would probably be the expert, but from my days at GM I do not remember any G-bodys ever being shipped overseas. Good chance that a private owner/collector has done it but best of my knowledge GM never did.
I haven't seen any. I've been doing tons of research on the G-Body thanks to AlGores invention of the internet and have come up with zilch on RHD G-Bodies. From my understanding there is a cottage industry in Australia of converting cars to RHD over there. The dash pads are hand made and can cost up to $5K just to make a RHD version. I'm no expert but it appears to be some type of law although I'm baffled on the cars with the words LEFT HAND DRIVE painted on the back of them. Kind of like tractors with the orange triangle here in the states. You always hear the myth of they are still building 55 Chevys down in Argentina. Well as far as I can tell the G-Body was only built in North America which might explain why there are no factory built RHD G-Bodies out there. I did snag a RHD Saginaw 800 steering gearbox out of the trash dumpster last year. It was from a USPS van so there are some of the specialty parts out there anyway.
I found these over on eBay.au . It gives you an idea on what it takes to convert a car over to RHD. If you click on the home page you'll find that 99% of the Yank Tanks over there are still LHD.
I browse the eBay Australia and United Kingdom sites about once a month and I have never found anything connected to a TR there. I wonder how many made it over there? I've seen a few old GS and GranSport Buicks but never a turbo car.