I didn't know there were any new planes. There are some color schemes though. Is that what you mean?
I too am new to RealFlight but I did figure out how to use the color schemes. I download the G3X, open it then save the included TGA picture as a DDS using Photoshop (toss out the JPG). Now place the TGA, DDS and Colorscheme in the ColorSchemes folder inside RealFlight's main folder.

I'm confident that there is an easier (right) way but my system works even though it's a little clunky (:-).