Lau discovered his L1128 on 3/5/1977. His notes go on to say that "I regard this taxon to be a form of Mammillaria supertexta. I had shown the habitat to Werner Reppenhagen. He described the plants in 1987 and compared iyt in the original description with Mammillaria huitzilopochtli".
Of course these days, both lanigera and ignota are subsumed into M. albilanata ssp. oaxacana, and I think this is correct. This species is very variable, and across Oaxaca you will find all kinds of variability of this subspecies.
Why Mesa Graden have decided to change the name in their listing, I don't know.