Noble Shaykh may Allah preserve you, I read in a book compiled by some of the students of knowledge consisting of your Fatawa, and the Fatawa of Shaykh ibn Baz, ibn ‘Uthaymeen and ibn Jibreen, that you say that reciting this Ayah:

Indeed Allah and his Angels send Salaat upon the Prophet.

Reciting it at the end of the Jum’ah Khutbah is considered to be an innovation, because the Prophet - ﷺ - never did it. 

Is this Fatwa correct?

Yes, for a person to conclude the Khutbah with this Ayah has not been reported. It only comes at the beginning of the Khutbah, it comes at the beginning of the Khutbah. As for delaying it and concluding the khutbah with it, then this has not been reported.

However, if he does it once in a while, there is no harm, but to habitually do it is not permissible because it has not been reported.