Good timing, I guess, as these have just been discontinued, and there is one last batch at the phosphater today. The gent on the phone told me of 3 dealers that have big backorders that should be filled in about 14 days.
If you want one, I recommend placing backorders now! I can't make any guarentees, as I am also trusting the backordering system, but this is the last call for Armalite clamp on FSBs.
DSG Arms allows backorders via the web (what I did), but the other two dealers don't. They may take backorders over the phone, but that's also a maybe.
$45/ea at both
http://www.riflegear.com/p-927-armalite ... crews.aspx
and
https://dsgarms.com/armeu0240mpkit
$59/ea at
http://www.customar15.net/shop/sights-a ... gas-block/
Good luck!