(During the edit conflict, I came to the same conclusion -)
 Can anyone access http://www.retratos.org/about.php or http://www.npg.si.edu/exhibit/curex15.htm ?  (mental note, exhibit was at Museo del Barrio, among others)
 Can anyone access the book mentioned here ? http://guest-gallery.blogspot.com/feeds/posts/default  (I suspect that Boufton may be a typo for Boulton, a prominent Caracas family).  There are sometimes harsh criticisms of his work. In "los retratos de Bolivar" by Alfredo Boufton, there is the comment "A. Meucci was one of Bolivar's painters with the least realism. His drawing is often imperfect and his brush of a reduced and poor impression and colour blending".
 Not here, but this site could be mined for a new image:  http://venciclopedia.com/index.php?title=Categor%C3%ADa:Retratos_de_Sim%C3%B3n_Bol%C3%ADvar
 This book might have it, if anyone can access it: http://yalepress.yale.edu/yupbooks/OnlineCatalog.asp?catalog=882562
There are so many of them, that looking for one author probably isn't a good use of time; why not take another PD image from the sites above with a known author?   could help (if you all are nice to him -)   (Talk)