I think I got it now. It is pretty much just a different way of phrasing it.
Page 294 of the 2020-chevrolet-silverado-owners-manual.pdf
GM only "requires" a weight distribution hitch for a 1500 series truck when the trailer weight is over 7000 lbs.
GM does "Not require" a weight distribution hitch for a 2500/3500 series truck.
So the GM door sticker only has one tongue weight on a 2020 2500/3500 truck.
Page 16 and 17 of 2020-chevrolet-trailering-guide.pdf
For example, 2500 Trailer Weight Rating of 14,500
Trailer tongue weight should be 10% to 15% of total loaded trailer weight up to 2,000 lbs.
So Tongue weight of 1,450 to 2,000. It could be less due to optional equipment and other weight limitations.
There is this in the owners-manual page 291.
"Do not exceed a maximum trailer tongue weight of 567 kg (1,250 lb) for a conventional trailer hitch."
So, the 2020 GM 2500HD Dead Weight Hitch - Max Tongue Wt specification = 1,250 lbs at least.
Door stickers can say more than that, say 1,850 lbs, so it is strange that 1,250 lbs is in the manual.
1,250 is well within what I need.