They were as I recall. I've been thinking of using a 3/4" x 3/32" piece of aluminum running along the bottom edge to stiffen and prevent any dimpling of the cover. The bottom edge is straight whereas the top edge isn't.
By the way if you have a 1955 and newer engine and you need (or want) a new side cover, Eckler's has them in chrome for $10.57 each plus shipping.
Ecklers 235 Chrome Side Cover on SaleThey also have chrome valve covers that are reduced.