What The Serial Number For Mount And Blade Is The Bi-metallic Pilot-flame Sensing Switch In My Gas-fired Gravity Furnace Replaceable?

Is the bi-metallic pilot-flame sensing switch in my gas-fired gravity furnace replaceable? - what the serial number for mount and blade

My gas furnace was installed in 1950, gravity. It is a Janitrol model GDS100-15 Type S 1252B0111 serial number, Surface Combustion Corporation, Toledo, Ohio produced. It uses a bi-metal switch on the pilot burner for the presence of pilot light is mounted. The switch is connected in series with the solenoid opening and prevents the main burner valve when the pilot flame goes out, a security feature, obviously necessary. I would not change even a drop-in replacement for, or an electronic infrared flame sensor that requires no direct contact with the pilot flame. Suggestions, please, but do not suggest that I am my stove gravity ineffective (100,000 BTU, 75,000 BTU output) with a new forced air furnace and air conditioning. We can not afford to do it now.