I bit the bullet and went through all 100-odd guitar music publications I've
collected over the years, from publishers around the world on every continent,
across multiple genres (although admittedly mostly classical and South
American). The set includes many volumes whose purpose is purely
didactic. And yet I was only able to find three books that use this notation.
So I suspect that "standard" isn't exactly the right word to use here. :-)
It's probably better to say that it's the "correct" way of guitar notation -- one
that is satisfying from a theoretician's standpoint, but rarely used in practice.