anyone know if these are silver hallmarks

capital B - Rat - Crown - JS&S - These are on some old forks. Also the name
PRADA with NV & TS

No, it’s an electroplate mark. JS&S is J Sherwood & Sons of Birmingham. The beaver (not a rat) is a trade mark of theirs. NV&TS is Needham, Vale & Tyzack of Sheffield. Not sure about PRADA though.