Nope, and I don't even suggest rats*, unless mice are in short supply, etc. A diet of appropriately sized laboratory mice will grow perfectly healthy and vigorous corn snakes. A lot of us on here have experimented for a lot of years, and most of us now feed only frozen/thawed mice.
*Nothing wrong with rats, but a few points -you may wind up with a snake that gets "spoiled" and doesn't want mice or dislikes fur. And small sizes (like pink rats) have no developed bone like a similarly sized mouse, so less calcium/phosphorus and they are a bit more fatty. Plus rats are more expensive, and my personal bias -they are really smart. Seems a shame to use them for food when there's a more biologically appropriate food with about 1% of the brain power/personality.