American Standard shower escutcheon trim

I have an American Standard shower valve, the escutheon plate and handle are in rough shape, how can I find the valve series number, the screws that hold the escutheon plate to the valve are at roughly the 10 & 2 oclock positions, I contacted American Standard and was told they do not make replacement trims for it does anyone know of a third party supplier that makes replacement parts.

thank you in advance for any assistance you can provide
Mike