It appears to be a 38 Safety and with that serial number, it would be 3rd Model, made from 1890 to 1898. That would qualify as an antique revolver. There are at least 3 things wrong with this 38 Safety.
First, it is likely a cut-barrel gun since this model is not noted as being offered in a 2" and were not available until the 5th Model. Check the top rib for a missing or partial patent stamping. Second, the stocks appear to not fit the frame, so at some point replaced. Last, the plastic sideplate is, as described above, an attempt to replace a missing sideplate. That type of plastic was not available in the 1890s so the factory could not have manufactured any gun with plastic parts.
You have a very heavily used 38 Safety that proves that S&W made quality revolvers capable of functioning perfectly for well over 100 years.