Parts for the model 1892 are tough to come by, especially if they are mag tube parts. Some parts for model 1892's can be found at Wisners Gun Parts. They have an internet site at: http://www.wisnersinc.com/
If I understand your question correctly,you have a Marlin lever action rifle chambered in 38WCF(38-40).If that is the case,then you have a Marlin model 1889 rifle,that was made in the year 1892.
With the serial number that you provided,I would say that your marlin model 1892 was made in either 1907 or 1908.
Your Winchester model 1892 rifle was made by Winchester in 1913.
With the last recorded and dated serial number for your rifle being 355,300 in 1906,I would have to say that your marlin model 1892 was probably made in 1907.
I would start my search at E-gun parts.com(Numrich Gun Parts Corp.).
The Marlin Model 92 lever action was convertable from .32 rimfire to .32 S&W or .32 S&W Long by changing the firing pin. Originally made as Model 1892. Made from 1892-1916, and depending on condition, a rather valuable rifle.
50-5000 USD depending on EXACTLY what you have and its condition.
I would start my search at Numrich Gun Parts Corp.
With the serial number that you have provided,your Winchester model 1892 rifle was made in the year 1907.
1914
With the serial number that you provided,your Winchester model 1892 rifle was made in the year 1917.
your Winchester model 1892 was made in 1896.