I'm not sure about the US spec, but on the UK 748/916/996s There are some large rubber bungs that are fitted in the air tubes when the bikes are new. You can check if these are fitted by removing the tank and looking into where the airtubes meet the airbox. You'll need to seperate the 2 halfs of the airtubes to remove them.
You'll know if they're there as these are fairly substantial pieces of rubber that are designed to restrict the airflow into the airbox.
Most bikes would have probably had these removed though I reckon.
I think that US spec bikes do have diferent specifications to the Euro equivalents (for example the Bostrum 998 was a 998S in Europe, but only a stock 998 in the US) - but I'm not sure about the 996S.
Shazaam, Skidlids, you boys are usually pretty good on this stuff.
The rubber restrictor annulus on the superbike inlet runners are designed to reduce air induction noise to meet Environmental Protection Agency legal limits. These are not inlet restrictors designed to limit performance like those used recently on some Japanese bikes to meet maximum speed limits. The superbike blocks merely increase the velocity of the air as it passes through the device but reflect sound waves back to the engine inlet. Said another way, the pressure drop across them is very low as opposed to a high pressure drop created by a dirty air filter. If you take out the restrictor blocks you’ll get a nice intake growl, but not much else.