In the Summer 2004 Toscano catalog, on page 17, lower right corner there is a
photo of a relief sculpture entitled 'Libertas' Angel with Crown, artist unknown.
Further, it states late 19th century--"angel of liberty offers a crown
to the heavens..." Can a more specific indentification be made/what is
the significance
of what the angel is doing?

I do not have access to the catalog which you mention. Does the statue
resemble this one?

http://www.engfrosh.com/1999/groups/Nike/nike.gif

No it does not resemble the image you sent.  This is a vertical relief and
the figure holds the crown in both hands high above her head as she
looks at it.  The wings are also contained within the vertical
composition and are cropped--merely suggested in a linear fashion.
I am mystified by the phrase---"offers a crown to the heavens..."

The image is available on the Toscano online site, though you have to
do a search within the site on the word "Libertas". Frankly, it looks
to me like a typical 19th century neo-classical sculpture, and if
Toscano say that the artist is unknown, then presumably that is the
case. As for the name of the piece "Libertas" and the description
"angel of liberty offers a crown to the heavens", these may be
Toscano's own ideas. To me, this doesn't look like a 19th century
angel (the breasts are too exposed), but could be Nike, Goddess of
Victory (as is the image suggested by Pinkfreud) who is usually
depicted holding up a crown or wreath.

Thanks for finding that, Geof! 

I agree that this doesn't look like the typical 19th century angel.
The holding of a crown or a wreath aloft is often symbolic of victory,
as in many depictions of the goddess Nike. Victory and liberty aren't
synonymous, but if this is indeed a rendition of an angel representing
liberty, I would assume that the crown has the same triumphant
meaning.

Thank you for your clues, Geof and Pinkfreud;
It may be that Toscano embroidered some copy. 
ochas