[Phono-L] mahogany Triumph on Ebay, Nickel plated

[Albert]

I am not an advanced collector when it comes to special finish machines, but 
I am very interested in the Nickel plated Triumph that is currently on ebay. 
Is there a way of knowing that the nickel plating is factory or something 
aftermarket or done recently.  If they were indeed special orders, would the 
serial number give a clue? Were all Mahogany cases model A's or B's?  Is 
this machine the real deal?Thanks for the advice. Al Menashe