I just acquired this cup and saucer set. Each piece has the double Louis mark with either an ‘A’ or ‘B’ . From my research these letters indicate 1753 – 1755. However, I can’t find any similar Sevres pieces. Each cup has a hand painted palace; Versailles, La Roche Foucault, Pierrefonds, and Chenonceaux. Does anyone have an idea of their value? Thank you.