I modified my P365 with a Sig flat trigger and a M*Carbo trigger spring kit. How would they know it's modified. Do you think they are going to take the gun apart and inspect it. The answer is no. They will check the gun to see if it functions and test fire it. They will then examine the controlled projectile shot from the gun to the projectile that was removed from the person who was shot to see if it is a ballistic match.