<https://masi.vuse.vanderbilt.edu/images/0/0b/EECE_252_Final_Project2.pdf>

Page 2 spectrum plots.

Effective RF electromagnetic power profile is effectively the same for baseband audio content modulated by AM or FM.

Question, Is this right?

\*\*UPDATE

Based on this, 

"a 1 kHz tone at maximum volume would make that frequency vary by plus or minus 75 kHz.  So 1,000 times per second, the carrier wave would sweep up to 97.175 and down to 97.025"

museumofbroadcasting.org/fm/fmstereo.html

I would conclude that the RF power envelope should show something very different from FM to AM. In fact, the FM power plot should literally be flat, or spread spectrum power.