No way! The long slender shape of the head, overall body shape, finely-tipped tail (instead of a button that will eventually become its first rattle) would be a dead giveaway even if you didn't know the markings. Go look up baby rattlers on line and you'll see what I mean.
Here's something to keep in mind.
With that Snake coming in from who knows where, you're going to want to be sure nothing that was on the snake will transfer to the rats, and then get passed along again.
Long shot, but it happens.