Cars are shown as being both LHD and RHD; Turkey has always been RHD.
Barney says that he is now a widower, and that his late wife was Grant's mother. But if Grant's mother was either of the two women Barney romanced during the original series, Grant would be from seven to ten years younger than he is. However, it is possible Barney wasn't married to Grant's mother before his birth, or that Barney wasn't strictly faithful while away from home. It's also not stated when Grant was born, so he could be younger than Phil Morris.