From a distance they look identical.  On closer inspection, the phone on the left is a copy.  The case is unmarked, and of inferior quality.  The base and internals are from a "recycled" WE 302 (turned sideways).  The dial is an AE, which is commonly found on the "real thing."  Even the handset is a genuine North -- although I've seen them with Western Electric F1 or Automatic Electric handsets -- whatever was available.

NORTH DESK SET -- Bottom View
 
 
 
 
 
 
 
 
 

WESTERN ELECTRIC 302 -- Bottom View

NORTH BAKELITE SETS have distinctive vents, a generous hand grip and the cases are well marked, although in small letters, along the bottom edge. 

Click here to see other, less common,  North sets.
 
 
 

COPIES are usually plain (or have a non-north logo, see below) and have a small handgrip.
 

Dials may have a visible external bolt on the fingerstop.