Vintage Pyrex 0503 factory Error?

Vintage pyrex number 0503 and lid 503-C. With possible factory error ? In great condition no chips or cracks and I do not see any scratches. It is a yellow rectangle dish and clear glass lid with lines on the side. The dish is bowed or warped on one side ( see last two pictures that I am pointing in). I was told this could be a factory error and make this piece more valuable but I honestly have no idea. The bow does make the lid fit a bit odd. I do not know much about Pyrex and I am not a collector. I got these pieces from my grandma. If you have any questions please feel free to ask. outstanding for everyday use. supreme materials and excellent craftsmanship ensure long-lasting durability.