Well, folks, the Model III, Level I ROM is no longer an extinct species!  I have
purchased a Model III, Level I machine and have made an image of it's ROM.

Before I continue, please allow me to thank John Benson of Australia for locating
this machine.  He notified me of the machine for sale so that I could purchase it.
Without his locating the machine, I would never have been able to obtain the
machine and image the ROM.

It appears that the ROM is a 4K ROM, even though it's plugged into the ROM A
socket on the Model III motherboard (which supports 8K ROMs).  I say this because
when I read the ROM, the A12 line *appeared* to be ignored.  This makes sense because
Model I, Level I ROM was only 4K.  But, it'd be nice to see a datasheet on this ROM.
I couldn't find one anywhere.  The chip number is SCM91616P, which is a Motorola ROM..