I called today and was told that my ammo and mags shipped yesterday and would be delivered today (I already knew that, if I had checked my email - d'oh). I also was told that I couldn't have a tracking number for the AK, since some people apparently try to take that to UPS to reroute the package away from the FFL to avoid the NICS.
I totally understand - had no idea anyone could try that! I was told it was being delivered tomorrow, most likely, as it shipped yesterday as well! WOOHOO!
Thanks again for all the info! InterOrdnance was helpful too here:
www.warrifles.com/forums/showthread.php?t=37656 (found that thread by Google search and piggy-backed on it to get my answers). I found out the following:
(a) Any AK furniture will fit this STG-2000-C, including the Tapco folding stock and CAA AG47 grip I just bought.
(b) The flash hider is put on with a crush washer AND a paste to prevent its removal. They say it CAN be done, but it takes some real manpower. It has thread size 1/2 x 28.
(c) AIM and InterOrdnance make a great team and are both awesome about replying to questions!
Thanks for all the help!
ETA: My FFL-holder emailed me and said the STG-2000-C arrived and is logged in. Plus, I got the ammo and mags today as well! Sweet - fast shipping! That "delayed shipping" warning on the front AIM page had me worried, but this rolled out fast.