You are allowed an exemption of $800 if you are married and your wife went with you are $1,600 duty free. If you are at the $800 level they do not charge duty until after $1,000, so If you spent say $1,300 on the drone there is only a duty charge...
To determine if your drone is in CE or FCC mode, open the transmission tab in the drone's control app (like DJI Fly) and look at the signal strength chart. If the -90 dBm line is positioned close to the 1-kilometer mark, the drone is likely in CE...