I am using SmartRF Studio 6.13 for CC2530 and CC2591. I do not see any means to indicate usage of CC2591 range extender device in CC2530 window. (I see it in CC2520 window).
The release notes indicate that support for range extension (CC2591) was added in SRFS2530.dll 1.1.0.0. SmartRF Studio shows SRF2530.dll version as 1.1.1.0.