Physically 2M styli will fit on alternative 2M cartridges bodies, but 2M Series cartridges’ engines, coils and magnets configurations are not quite identical: Red and Blue are identical, so are the Bronze and Black and so are the true mono variants 2M Mono and 2M 78.
 

2M Silver phono cartridge is an OEM (Original Equipment Manufacturer) model that takes most of the characteristics of the 2M Red. 2M Silver's special feature is silver plated copper coils, the same coil wire material as in the 2M Bronze and Black models, with a reduced number of windings.