The simple answer is no there is no "standardized" pattern. Nearly every quilter likes to add his or her touch, something they like better, thinks works better, thinks looks better, can do easier or better etc.... The variations are endless. There are some old patterns saved or found that have survived, and they would be considered by us to be "classic" or even "standard" but I suspect in their day they were just variations too and they happened to be the ones that survived to our day.