Hi! Would anyone know if these are authentic? The lack of serial number at the back is what's making me question the watches.

 

These are often market Argent, Plaque d’Or. Silver, gold electroplated. Many jurisdictions would not accept the 18 karat gold electroplated marking on the backs of these cases. Check with a Cartier dealer would be my suggestion. The questions pertaining to these, regularly show up on the MB. If you search the archives using the magnifying glass above this page, you can find numerous previous threads discussing these.

 

Thank you sir I will search now