Hood scoop question regarding rivets

[Whaler]

Hi I have drilled the holes for my hoodscoop, thru the hood opening and the aluminum liner on the under side of the hood.

I was told to use a backing washer with the all aluminum 1/8" rivtets. Did anyone else use backing washers? I could see the need if it simply fiberglass. But with the aluminum skin/liner is it still needed?
Are the backing washers now a better choice on the top or head side of the rivet? Thats where the fiberglass and paint are at risk on squeezing the rivet off. The washers I do have are a small SS #4, They fit the rivet nicely.

If possible can someone show me a close up pic of thier riveted hood scoop front and back side?

Thanks

Tim