There are extremely few European countries that drive right hand side. United Kingdom, Ireland, Malta and Cyprus are, I believe the only ones. The majotity of rhd countries are actually in Africa. I'm guessing Australia will be the highest non USA and Canada export sales for the rhd model. As far as manual transmission being harder to convert, the only difference would be the clutch pedal as the transmission position and shift pattern are exactly the same with both drives. If history repeats itself, there will be less than 600 Corvettes shipped out of North America. The other alternative is if GM wants to get a bunch of C8's in other countries to promote future sales, and if smart, that would be a good idea. Corvettes best production year was 1979 with just under 53,000 units produced. If indeed they only produce 30,000 or so C8 units, they won't have to ship anywhere. The first year of C7 produced 34,839 units. Of that number, only 1181 were shipped to Canada and less than half that to European markets and they disappeared pdq.
With order production now rumoured not to start until December, Cdn delivery will not be until at least April and if history repeats and only 1200 units come north, then it will likely be a sad day for anyone who didn't have their deposit down long before the July reveal. Yes. Some dealers are still getting buyer's hopes up making shallow promises and taking deposits but IMO, consider the 2020 run long gone. At least you will have a head start on the 2021 release.