19389610 is not a relevant OE # for the Gen6 ZL1 according to my accurate OE GM parts lookup. As you mentioned it is an AC Delco Gold pad. From the pics of the Gold pad, it is not the same pad as it is atleast missing the slots. And I do not see the HP1000 stamping in the backing plate, but the pic is not super high quality. And the pad material
looks different.
Gold Pad
OE ZL1
It is a lot less expensive than the OE pad, I can see the appeal to try. If you're not tracking it might be an acceptable pad.
The #23399101 (AC Delco 171-1192) is still the relevant OE pad for the typical ZL1 J6H applications.
And for the rear, FWIW, is still #89047744 (171-0882).