Dino has been working on this and the Long-EZ for MSFS since early in the year, back during alpha testing, when the developers who signed up first got access to the SDK. They are MSFS-native models. The MB-339 is of course a reprocessed/redone version of Dino's previous work, while the Long-EZ was a open-source model that Dino acquired in order to use as the first aircraft he worked on developing-out for MSFS.
Beautiful shot, Jan! I love the real reflections in MSFS.