Child's naturalization certificate

[checke]

Background:

My wife, US citizen at that time, and I were living in the US in 2010. At that time my 2 year old son an I became permanent residents. We applied and got a US passport for our 3 year old son with his permanent resident card (under current law a child that is a permanent resident of a US citizen, and that child is lawfully in the US and in the custody of the US citizen parent automatically becomes a US Citizen). I became a US citizen later and we moved to live in another country.

I currently would like to apply for my son's naturalization certificate. Since we do not live in the US, I am hesitant to use form N600 because he is no longer a permanent resident (we still have his card, but he is a US citizen) and whenever we travel to the US use his US Passport at immigration.

Should I fill out form N600, with our place of residence outside the US and then send with it a letter explaining the timeline of events? Don't want to spend the filing fee and time if we will get rejected. Any advice is welcomed!

[Jot18]

If your son already has a US passport why you need to get naturalization certificate?

[checke]

If your son already has a US passport why you need to get naturalization certificate?

The Naturalization certificate is proof of his citizenship in case his passport is lost or stolen or by any reason we/he forgets to renew it in time. Also, passport is given by the State Department and can be asked to be surrendered at any time by the State Department.