Terracotta Sculpture; Élisabeth Vigée Le Brun.

This terracotta bust on a marble base resembles a work by Augustin Pajou which is on display at the Louvre dated 1783. I believe it represents the famous French potraitist Elisabeth Vigee Le Brun. The bust with base is roughly 25 inches tall by 16 inches wide. I purchased the bust at auction in Washington D.C for $400 in 2009. The auctioneer had no substantiating documentation about the piece. I was able to link it to the work by Pajou through style comparisons from Sotheby's Janury 29, 2010 catalog of Important European Tarracotta and Bronze Sculpture. 

I am interested in any history of this piece along with value at auction as well as replacement/insurace. Thank you in advance!!