No...
Almost all of the amels I have plus the ones I hatched out last year were definitely "normal-sized." A lot of them grew at faster rates than the rest of the snakes. For example, I have a 2003 amel that is 31.9 inches long and weighs 196 grams. I think it mostly depends on if the snake is a good feeder, how often its fed, and how much it is fed.