I had to deal with this last year- I ordered an AC Delco alternator (from Rock Auto ironically) under the assuption it would be a quality part.
It was a turd with a battered case, worn out holes and subpar parts and a reman in China sticker.
For reference I had two AC Delco units that I had from a job over a decade ago and the parts were a MUCH higher quality. Threads were sharp, diodes twice as heavy, stator neatly painted, etc.