What's the "Hollander #" as compared to the "OEM #"?

[Wasatch Rebel]

I've been looking for a used part and I ran into the OEM #1770062100 AMZ001-2580512-1, followed by the Hollander # which is 319-58128C. What's a Hollander number?

 

[TheDurk]

Hollander Web Site

They are one of the biggest used parts network operators for salvage yards. Good place to hunt for used parts or find yards.