I would like to know if any of you have information on Indian motorcycle foundry forge stamps that were used by companies under contract for the verticals. Jim Preussner told me that an original marking was an M enclosed in a C. This may have been an original first contracted company to make the accessory center stands for the 149, 249, Warrior and others.
I have also seen an SDF overlapping stamp lettering on vertical side prop stands and other parts such as the shift lever, brake pedal and other engine parts.

Does anyone know what the letters mean?
Is there a source of company information that preserved records of companies under contract?

AMCA 36450