I've got almost the same grilles on my cab, maybe a little bigger. I love the way they look.
As far as authenticity, they aren't vandal-proof, so I doubt they would be used in a retail environment.
I feel that as long as the controls, cabinet shape, and monitor are close to authentic, the cab will look and feel authentic to a casual observer. That is what matters to me.
EDIT: Photo at
http://ww2.santoro.com:8888/Mame/images/IMG_1392.JPG The flash makes them seem very obtrusive, in real life, they blend into the black paint and are just noticeable enough.