Look like USA spec bikes. I had a RD250E briefly in 1987, 5,000 miles and in mint condition. Wish I still had it. Mind you with the exception of the KH250 I also had in 1987 I would love to still have all of the biles I have ever owned – even the Superdreams (I had THREE) and VF1000 (the flying Hostess Trolley). Do you know Yamaha RD350s are made in India as the Rajoot 350? Must be like an R1 there!
You are right Radar… the RDs were like the R1 here. They are out of production for a long time now… but are still kept alive. One of the sites is as rajnish pointed out. A good friend of mine has a site dedicated to the RD at https://www.bikeszone.com .