Decamps Engraving Questions

Maybe this post would be better placed under Art Valuation, but it looks like nobody ever goes there.
I have a lithograph or engraving by Alexandre Gabriel Decamps. I only found out for sure it is really his work by finding one other version of the piece, for sale on eBay in France ( Edit [Moderator]: Link removed ). The eBay title says it's an engraving (by LAROCHE) and I am of the understanding that the engraver's name is always shown on the piece. Mine doesn't have an engraver's name, though. It has a title ("Bassets"), the artist's name (Decamps), and on the top left it says Galerie Durand-Ruel.
1. Can I assume that mine is an engraving?
2. Any idea why the engraver isn't listed?
3. The eBay one in France is black & white, while mine is colored. Does coloring make a difference in the value? (I am aware that mine has some damage). Thanks for any insight...