I presume you mean the anonymous pastel drawing with the centre parting and blue jacket with buttons? It does look very like the bust David D'Angers said he made from a pastel borrowed from the Le Bas family - it also looks very like the drawing one book I have says was drawn by his landlady that isn't shown here (though I suppose it's possible the drawing/etching in the book was made from the pastel by someone else, rather than being a preparation drawing for the pastel...)