I just did a bit more historical digging, and found others who commented that their Manfrotto head indeed came with some sort of grease as assembled at the factory.
Apparently at some point Manfrotto changed over to polymer rings, which coincides with the 'grease free' description of their head.
I did a bit more searching via Google of 'Manfrotto grease' and indeed found a couple of places that referenced Manfrotto part numbers for grease in a capped cup, but unfortunately found zero detail about the grease (which was listed with a $35 price)
In addition there is some kind of grease specifically for Manfrotto fluid heads for video "Manfrotto MVH502AH Fluid Head (Grease Replacement)"
So obviously Manfrotto indeed used to use grease, even if the 'kids' there today know nothing about it, and their blurb says maintenance free. Good luck trying to speak with Manfrotto parts to get a description of the intended use of each of the greases, (R116,23; R3,3511; R101,857)
I found the 'Friction Grease R3,3511', listed on a German site, but the accompanying illustration shows a Manfrotto TRIPOD, not head.
Same web site also listed 'R116,23 Manfrotto Drag Grease', and again the illustration was a Tripod, not head.
So the only Manfrotto part to investigate with them would be R101,857. The 'high viscosity black' does not sound promising for a tripod head, though.