This is a HP rebranded disk, and ID in Bios (GB0160EAPRR) is different to the ID on label (WD1602ABKS). I guess this is where the confusion set in, but I am surprised that a company that rate themselves so highly failed to even reach the right diagnostic.
Personally I think you are lucky, if the parts
were sourced under inaccurate diagnostic (
something about heads, pcb's......blah blah blah) then your data may have been lost forever.
Also, since you were able to source the part so quickly, maybe you should ask them if they have any jobs going
p.s. Good job @ retrodata.