My initial research indicated that H&K and Benelli ended their relationship to import Benelli products into the USA in 1997-1998 timeframe. Digging deeper I saw that H&K was involved in the military contract to import the new Benelli M4 in 1999, which is why I deleted that post as I had discovered it was incorrect after further research. There's nothing to indicate that any USGI contracted Benelli M4s/M1014s have ended up in civilian hands.
In your OP you were inquiring where to find "an HK import for a Benelli M4" as if there's any USGI surplus Benelli/H&K imports (1999 DoD contract) "on the civilian side". Then you post "I never once said (the 1999 military procurement contracted Benelli M4s imported by H&K) were on the civilian side." No you did not, but you implied that. I'd love to see any proof at all that there are any surplus USGI Benelli/H&K import M4s which ended up on a Form 4473. So kindly show us where and how the 1999 Benelli M4s imported by H&K have been made available to civilians as surplus.
The 1999 DoD procurement for Benelli M4s was for Benelli M4s with full length magazines and C stocks. The ban on more than five round magazines and C stocks (not folding stocks) on imported shotguns intended for civilian sales goes back to the gungrabber era, 1989-1994. Sales of the unneutered Benelli M4s with FL magazines and C stocks to us lowly civilians is generally prohibited (especially surplus sales by .gov or .mil). I'd love to see where one ended up in civilian hands, those things do occasionally happen.