From my Serbia and Forgeries blog post......
http://bigblue1840-1940.blogspot.co...fSerbia.html
Genuine vs ForgeryTyler (Focus on Forgeries-c2000) points out two signs for the forgeries.
The horizontal line under "APA" in the right upper portion of the stamp is shorter in the forgeries (1.2-1.4 mm vs ~1.5 mm).
And there is an obvious "nick" in the right frameline 6 mm below the top right corner. All my forgeries show this.
Genuine vs ForgeryI found a another "good" sign in addition. On the jacket design of the forgery, there is a thick vertical curved white line separated in the middle. This is not seen with the genuines. All of my forgeries show this quite clearly.