The non-graded archival master (NAM) is the starting point of the IDT generated ACES files
(sometimes with an exposure grade to just set the luminance scale correctly for ACES) So the ACES file in AP0 before shot by shot grading is the NAM. (so is an ACES file with linear offsets to deal with exposure so it looks correct with the RRT/ODT. But NOT if there are color/contrast/gamma adjustments.
The Graded Archival Master (GAM) is the output of a grading session (per shot). There can be incomplete versions of this where not everything is yet graded or have a non-final grade. SO technically the GAM is only on the delivery. Rendering to AP0 doesn’t mean anything from a grading perspective.
For details, see Netflix