The RX3 and RC3 share an engine but have different platforms, the TT250 is totally different. Zongshen did not decide to bring these bikes to the USA CSC did.
They also are bringing over the RZ3 that also shares the NC250 Engine, for 2017, it does not share a frame with the others, they are all different other than the engine.
Zongshen has a 450cc version in R&D an RX4, they also are developing a 400cc twin.
http://www.mojie.mobi/upload/image/2...1333283328.jpg
It is not uncommon for people to make assumptions, The RX3 was not built to compete in Dakar. However, if the people at Zongshen want to garner more respect they may want to engineer the RX4 to do so. They could call that version a Marathon version.
These guys both of them should test the SSR250 with the NC250 engine on the trails they like to ride on. But they do not have to, it is a free country.