I can tell it had Delo from the black streaks.
My 98 12V’s first 50k had delo. After I ran AMZ/OIL 15-40 Diesel Marine. I did the KILLER DOWEL PIN at 100k. The inside of the front had black streaks. At 120k we did my Dads 94. It was spotless ands golden color.
My Dad used AMZ/OIL from the first change on.
Does it matter? No idea but that is what Delo leaves behind.