US 1930 Zeppelins

 Though somewhat uncommon this series was forged. Unfortunately most of the forgers are unknown.

Genuine issues

Forgeries

They can be identified by the poor lettering and background clouds.

Identified as a Panelli

This one sold as a forgery in a Kelleher auction for $750

Others

Fake die proof

This last one appeats to have been postally used?

Hawaii 1861 2c

Genuine Issues

1861 Proof

1863 Sc 27

1886 Reprint Sc 50

The 1886 required a new stone to make.

To tell if the stamp is an 1861/63 or 1886/89 one needs to pay close attention to the top right corner for changes in the 2 and side ornaments

Genuine stamps have the line just above "UKU LETA" ending below the label containing the "2" at the right hand side. 

On the left hand side this line starts a little above the label containing the "2".

Spiro Forgeries

These are the most common.

Aside from a very different facial expression,

The Spiro forgery can be recognized by the absence of a dot behind "KENETA". 

The "2" in the upper left corner is too far to the right (it should be in the center). 

The frame-line above "UKU LETA" ends too high on the right hand side.

Fournier Forgery

Thick border and letters

Two's and ornaments very different

S.A. Taylor Forgery

A wide eyed king

A's are faulty

Many breaks in frame lines

Torres Forgery

Looks identical to the Fournier

Sperati also made a forgery but I have not located any copy of one