Few thoughts. What about locked left/tight hand drive?
From what I have seen, the RA does defenately not have a righthand drive sibling- > LHD only.
The LX4&6 are based on the Lotus 7s. Which are RHD -> RHD only. Though these are usually self-made so it would be perfectly realistic to have both LHD and RHD versions of them. Unless they are direct Lotus 7 replicas.
FZ50 would probably be sold all around the world, so both are good. The same with the RB4, XFG and FXO.
UF1 is based on the original mini, which could be RHD only.
The XRT and XRT (and XRR as well) could be some American 80's sportscars not sold in Australia, Japan or in UK. LHD only. Or japanise.
But I don't see that in LFS you need to lock the driver positions in the cars. At the same time I don't like the fact that people switch from left to right all the time to gain more speed. IRL no one has LHD and RHD versions of the same car for different tracks, but in LFS everyone has. I don't like to drive on RHD but I could cope with it, eventually it would probably make no difference. I just don't like how easily and effortlessly you can switch the driver position in LFS.