To be clear, in its current config as sold they are compliant, when you add the extension, you do need to watch your parts count although many of the parts are now US MANUFACTURED by BENELLI USA (BERETTA USA) but getting proof is hard! if somebody told you you didn't need to do anything but add the extension, they were in error,not trying to get one by you. There is no nefarious plot in action.
You'll notice that almost all the articles are from 2008 to 2012. Before Beretta opened up their new US assembly plant. We've been told by our representative that they are now sourcing their plastics in the US . Which means the stock and the handguard are already US parts. But without Beretta adding USA markings to these parts or being willing to provide documentation, how do you stay lily white ?
A company named freedom fighter tactical built themselves by selling 922r parts, so use caution, as obviously creating fear helps them sell parts.
Now as you are adding mag extension you traditionally have to do 3 commonly replaced parts from:
Bolt
Bolt Carrier
Gas Piston
Trigger Housing
Trigger
Hammer
Disconnector
Forend
Magazine
Follower
Stock
Most people do forend (Botach or surefire), hammer (geiselIie) and follower.
http://www.brownells.com/shotgun-parts/trigger-group-parts/hammer-parts/hammers/benelli-m4-hammer-prod44723.aspxhttp://freedomfightertactical.com/products-page/922r-compliant-followers/the-freedom-fighter-tactical-922r-compliant-aluminum-shotgun-follower-for-benelli-m4-red/Remember mag extensions don't count as US part as you are not replacing a part, just adding. The one piece extensions WOULD be adding a part and would count as 1 of 3.
I think the biggest problem is it even if our reps tell their dealers that many parts are now sourced from the US , they probably use whatever they have handy so if they don't have the US part available they use the Italian therefore they're hesitant to certify any individual part as US made.
It does sound like I need to re-brief our staff on the shotgun and US parts compliance. I'll also reach out to our rep and see if they want to go on record .