Welcome G Family to the Newmar forum and irv2.
Congrats
on your new coach and many safe and happy miles.
My mud guard is mounted to the main C rails of the chassis. Not sure if the holes were already drilled or had to be. The guard is hung with chains and swings out of way when hitting low spot on road surface or driveway.
If you mount hard to frame mounting will snap eventually.
If you need any more help just say the word.
Some people consider all capital letters, that your shouting at them.
Enjoy the forums and do post often.