Sorry, I speed-read your first post and missed the part about you wanting moderators.
Some time back (maybe last Aug or Sep) there was some discussion on AGN regarding a revision of policies at U.S. Customs which was impacting the importation of air gun moderators, as well as some air guns which had moderators. They were not being allowed to proceed, but being 'turned back.'
A little later there was discussion on the site that Krale was no longer accepting moderator orders from U.S. customers.
My personal experience is that I ordered a specific Air Arms moderator from a U.K. dealer, and it shipped about the middle of last August. Spent a good amount of time in USPS Status 'Processed Through ISC Facility' (which actually means arrived at that facility), then the status changed to 'Inbound Out Of Customs' on 10/14/2020. And that is how it has remained to this day.
The vendor already refunded my money, so I'm not even following the shipment any more. Was it lost by the USPS? Did it get stopped by U.S. Customs because it contained a legal air gun moderator? If Customs stops something 'illegal' do they return it to the sender, or seize and destroy it?
I don't know the answer to any of the above questions. All I know is that I never received my moderator ordered from Europe last August. I don't think you have to worry at all about an Alphabet org door knock, but as far as receiving your purchased item, YMMV.
I have found Huma-Air to be great communicators. Drop them an email - If U.S. Customs is causing issues with legal airgun moderator shipments, they would know.