Close but no Ceeegar.
I show people this site when they are looking for Doubled Dies;
http://www.errorvariety.com/OFD/MD.htmlMy thought process is that the 2nd "hit" needs to be at the same hieght or just slightly lower.
Many will trumpet that IF the mint mark is doubled along with the date, it typically signifies a
Machine Doubling.
Under magnification, like a microscope, I look at the side where the doubling appears. If it looks shelvish, or looks like a payloader scraped the side of the date, mint mark or other areas, its highly suspect of
Machine Doubling, a common error.
Double Dies typically look pretty obvious. When you see one it will be a wider eye opening experience.
Keep up the vigilant hunt ! They are out there !!
In 1990 those rules have changed some, since the mint redid the way they slapped coins. <smirk>