looks like foam with aluminum tops for the big. possibly white acrylic for the bottom. the bottom looks a bit reflective.
The big ones are gloss white painted aluminum returns with flat acrylic or metal faces because you can see the reflection of the smaller letters on the bottom of the large "E". Small bottom ones are either pvc or matt white acrylic.
This, the big letters sure look like fabricated aluminum to me, those returns are too glossy and smooth to be foam unless someone spend an awful lot of time prepping and sanding it before painting.