No, it is definitely pieced corners to get the solid background, Rachel. Thus, Wheel of Fortune. :P
The seams are hard to determine because of the black background. I don't think the maker cut diamonds in order to piece the squares. Looks like the quilt lines followed a linear pattern on the piece. You are right, only Eddie can say for sure how the quilt was made. However, in due respect, I believe it's the Wheel of Fortune, rather than a Spider Web design.