Barr Portable Typewriters, Page Three.

Here is another advertising montage; original Barr-Morse materials from Chuck & Rich.
Early machines prior to s/n 2000.  A manual for maintenance in the hands of Richard Polt states that machines with serial numbers lower than 2000 possess a number of mechanical differences as compared to following machines. 
Barr Typewriter S/N 1258.  Chuck Dilts / Rich Cincotta collection. 

This is the earliest known Barr machine, and is one of only two made prior to serial number 2000 known to exist today.  It displays one very obvious design difference from later machines in that it does not have color-matched ribbon spool covers.  The ribbon spools simply mount on conventional posts and are held in place by small metal clips.
At right, the detail shots for the instructions found with S/N 1258.  Note that in the pictures, the ribbon spool construction is exactly the same.  Note also that the machine has a label on the front of the machine, above the top row of keys, which says "-BARR- Typewriter."  No mention of model is made.  One can also identify another feature of all Ithaca built machines, which is the use of white keytops with black legends. 

Notable too on only a very few early machines is the painting of the center of the type-bar segment in a color matching that of the body.