I do not have my research books available at the moment.
It is possible that Rockwell may be one of the companies that merged into International Silver Company and they may have documentation.
Not all of the ephemera from acquired companies are kept due to storage problems. You might want to check local libraries in Meriden to see if they were donated any of that material.
My reference books tell me that the Rockwell Silver Co merged with Silver City Glass Co to form Denorex Industries Inc. You might try contacting them for the information you seek.