Antique Sterling or Silver plated Wine Coasters

Got them from an estate with another pair that were antique (they were marked 1856). But these only have a makers mark of what looks like an anchor (see pics and see stamping description below). So not sure if they are silver plated or if they’re sterling. They are at least vintage, but probably antique. I didn’t do the research. Just need a polishing. LAPADA Guide to Reading British Silver Hallmarks - An "anchor silver stamp" is an assay hallmark signifying the silver was tested and marked by the Birmingham Assay Office in England, and it is found on sterling silver.