There is no industry standard, the main willow merchant constantly sends what it has, rather than what is wanted, the bat makers upgrade grades to boost profits, as do the retailers so best to ensure that whoever you are dealing with knows what you want.
We all like pretty grains, but we all like big light bats, crossing the two is tricky and harder than people think but at the end of the day it comes down to why you are buying a bat, to look good or to play well?
If you specified 12 clean straight grains in your bat you would get them, if you said grade 1 then your perception of grade 1 might be different to mine and many others so best to translate what you want with the seller to ensure you are both singing off the same hymn sheet.