To the best of my knowledge they are NOT available for civilian purchase as of yet. Not entirely certain what is holding up the process. Theres a forum devoted to the discussion of these things, they'll all have a way better grasp of the situation than I.
https://hkpro.com/forum/forumdisplay.php?f=118 There's also a specific thread dealing with this very question right now. https://hkpro.com/forum/showthread.php?t=84872