I don't think you have to worry about any switcheroo being pulled off.
Much of the steel I get from Dictum ( and Workshop Heaven) comes with the HT and data papers from Hitachi still wrapped around it. Some even comes in the original wrapping papers from Hitachi in Japan ... all written in Japanese.
The Takefu alloys are different form Hitachi ... but they both produce superb knives. The benefit of either one is an exact and guaranteed makeup that you know. The similarity in the names is because the same terms are used to note higher and lower grades. It can be confusing if the source isn't known, though.
The names Aogami, Shirogami, and Kigami ( and similar names) , meaning blue/white/yellow metal, are based on the old days in the Yasuki/Yasugi steel district when many of the workers could not read or write well. The steels were wrapped in different color papers to signify the purity level, and the papers were numbered to signify the degree of impurity (alloying). #1 was the very purest, #2 was very good, and #3 had much more alloying and trace elements. This was started before the days of metallurgical science, when the blooms were sorted by experienced smiths based on look and brittleness. They were surprisingly skilled at separating the steel types.
White was the purest. The grade designated the carbon content. White #1 was the highest carbon and purest steel made at the time. Only a small portion of production would be graded thus. It was rare and highly regulated as who could use it by the Guild. I think it still is to some degree.
Blue was white steel with other alloys added.
Yellow was the least pure, but still cleaner than standard "mill" steels.
Here is a good data sheet that shows the reasons for the various levels of alloy. Each change is for a reason to increase a certain aspect of the blade.
http://www.hidatool.com/image/data/pdf/White Steel vs Blue Steel Chart.pdf
I am not sure Murray can sell any of his Hitachi steel. He is granted an exemption to purchase it outside of Japan because he is a Guild member. It is also a selling point of his knives that he promotes.
