You've still got some time:
https://silencerco.com/free-suppressor-promotion/Product/s must be purchased through a retailer between November 15th and December 24th. A copy of your date stamped receipt and a copy of your Form 4 will be required at registration.
No purchase quantity limit, however, you may only submit 5 serialized items per registration. Purchases must be registered by January 15th, 2022 to qualify. SilencerCo is not responsible for late submissions. Products cannot be returned or exchanged for other products of similar value or for monetary exchange. Offer good in states that permit silencer ownership.