SEAL's operate under SOCOM, meaning they do not use standard issue gear, weapons or tactics. Like one of the earlier post states much is mission specific and based on what each member of the team prefers. There is no way of knowing exactly what model suppressor is used on a day to day basis, or even if that model is being offered to the general public. I highly doubt that some of the big companies like AAC are send the exact same suppressors to the NAVY SEAL's that they send to local dealers.
Actually I know for a fact they are not, most of the weapons manufacturers have to sign agreements with the government that they will not make the same gun for civilian sales that the military is using, ever wondered why there is no semi auto MP5's made by H&K, or why there are no M240B's being sold by FN?
The military also buys suppressors with different criteria in mind than civilian customers, sound reduction is typically lower on the list, POI change, flash elimination or reduction, weight, durability (how many times can it be dropped and still work).
The NSN number search will tell you contracts have been awarded to Gemtech, AAC, Knights Armament, Ops Inc, Smith Enterprises and Surefire.
You also have to remember one other thing when talking about government contracts, they are awarded to the lowest bidder, and lowest bidder does not always mean best for your money.