That's correct. The Wing Commander Saga team forked their code a little while ago (meaning they now have a separate code base from FreeSpace 2 Open), and since then soft particles, thruster distortion, and framebuffer shockwaves have been added to FreeSpace 2 Open, along with experimental builds that contain shadowing, not mentioning the various fixes and code optimizations that WCS has missed out on. WCS has also removed useful features from the engine such as custom launch flags and the mainhall ship model viewer, and it also is not compatible with the standard launcher used for FreeSpace 2 Open, requiring their launcher which has greatly decreased user options compared to the standard FreeSpace 2 Open launcher. They've also added very few features FS2O doesn't have, so general consensus on the forums that host the FS2O Source Code Project is that their code fork was pretty useless since their engine doesn't do much for either them in terms of features or you in terms of options.