The design patent you're referencing actually covered more than you cite. . . that was merely one aspect of a list of the Design parameters of the Design Patent, which included drawings, distinctive photographs, and the narrative description, as required by law to be included. The curve specifications of the rounded edges were precisely defined in the description. Color, sheen, polish, width of bezel, lack of markings, placement of markings, fonts of markings and sizes of text, all are included in a Design Patent. However, minor alterations by an infringer, say changes to a font or the logo, etc., do not sufficiently alter the design to avoid infringement. . . Design changes MUST be substantial and not merely decorative.
See MPEP Section 1503, and Section 1504 relating to a requirement for ornamentality.
"Entirely" in scare quotes on account of some ornamental features require text for description, usually surface treatment or texture. The design patents that I have prosecuted sometime contain elements that are not part of the claimed design, for context. This practice is usually accompanied by some text disclaiming the contextualizing material as not part of the claimed ornamental appearance.
The Apple design patents that I looked at just now (D618,677 and D618,678) didn't contain a logo or any text (text being a necessary prerequisite to font), and illustrated the look of an iPhone. It did include width of bezels on the display face, slots, earphone port, and buttons, but didn't include any display objects.
The design patent that really got my goat must have been a different one.