Earliest secret serial number

[55 56 PREZ 4D]

When did Studebaker start putting serial numbers on frames.
There is a post on another thread stating that a serial number was found on a 1951 Land Cruiser frame.
I'm not doubting that, I am only asking when it began.

[rockne10]

I've heard from a very reliable source that the secret serial number on my '33 is on the right frame rail under the passenger door. I don't doubt it, but I haven't found it.

[Green 53]

There is one on the frame rail of my 40 President.

Denny L

[Studebaker Wheel]

One on my ex '31 President.

[8E45E]

It must have been before 1931. The March TW shows a photo of the font blueprint which states 'secret location' in the notes. http://forum.studebakerdriversclub.c...-1-in-March-TW

Craig

[studerex]

Just found the frame number stamped on my recently purchased 31 president. The title used the motor number. Getting that corrected.