Nope, they are not. Your quote is taken out of context and the following appears in the same document (and on the same page):

Quote:

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The use of a copyright notice is no longer required under U. S. law, although it is often beneficial. Because prior law did contain such a requirement, however, the use of notice is still relevant to the copyright status of older works.
Notice was required under the 1976 Copyright Act. This
requirement was eliminated when the United States adhered
to the Berne Convention, effective March 1, 1989. Although
works published without notice before that date could have
entered the public domain in the United States, the Uruguay
Round Agreements Act (URAA) restores copyright in certain
foreign works originally published without notice. For further
information about copyright amendments in the URAA,
see Circular 38b.

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Quote:

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Jim, I think your sources are mistaken.

"Form of Notice for Visually Perceptible Copies
The notice for visually perceptible copies should contain all
the following three elements:
1 The symbol © (the letter C in a circle), or the word
“Copyright,” or the abbreviation “Copr.”; and
2 The year of first publication of the work. In the case of
compilations or derivative works incorporating previously
published material, the year date of first publication of
the compilation or derivative work is sufficient. The year
date may be omitted where a pictorial, graphic, or sculptural
work, with accompanying textual matter, if any, is
reproduced in or on greeting cards, postcards, stationery,
jewelry, dolls, toys, or any useful article; and
3 The name of the owner of copyright in the work, or an
abbreviation by which the name can be recognized, or a
generally known alternative designation of the owner.
Example: © 2008 John Doe
The “C in a circle” notice is used only on “visually perceptible
copies.” Certain kinds of works—for example, musical,
dramatic, and literary works—may be fixed not in “copies”..."

Quoted today from Copyright Office

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