Im not sure about Utah but in Ky you are required to notify the state police if ANY FIREARM is stolen ASAP Notifying the ATF dose not excuse you for notifying the state.
That is not correct. There is no law in Kentucky that requires you to report a stolen firearm.
As far as I know, only 10 states and the District of Columbia require you by law to report lost or stolen firearms: Connecticut, Delaware, District of Columbia, Illinois, Maryland (handguns and assault weapons only), Massachusetts, Michigan (thefts only), New Jersey, New York, Ohio, and Rhode Island.
Of those, only New Jersey has a law that specifically opens you to civil liability if your stolen or lost firearm is used in a crime and you didn't report it.
Now, there is a possibility in any state that regular negligence theories of common law apply to the situation where you fail to report to law enforcement that a firearm was lost or stolen. However, to prevail the complaining party would have to prove that reporting the theft or loss would have prevented the crime that your firearm was subsequently used in. That's a difficult burden. If you were negligent in storing your firearm and it led to the loss, then you might be considered negligent, but that's still a stretch since a criminal act (or two) is intervening. To be clear, I haven't researched the case law on this in any state.
I don't know if there's a specific provision of federal law that requires you to report a lost or stolen NFA firearm. (There may be, but I haven't researched it.) With that said, I would absolutely report a lost or stolen firearm of any type to my local or state police, and I'd absolutely report an NFA firearm that is lost or stolen to the ATF by at least their next business day by calling the NFA branch number (304-616-4500).
Remember: there's what you legally MUST do, and there's what you SHOULD do. Regardless of the law, you definitely SHOULD always report lost or stolen firearms to the relevant authorities.
Aaron