The first stamp is the Oldenburg 1/2 Grosch. The first image is the forgery and the second one is genuine.
There are a lot of differences. Big ones are the shape of the crowns and the shape of the ribbons above and below the denominations.
The second stamp is the Hannover 1/15 Thaler. The first image is the forgery and the second one is genuine.
The crowns are different as is the unicorn.
There are a lot of resources available for Old German States collectors. The APRL has an on-line catalog of available literature.http://catalog.stamplibrary.org/Inm...ch&xm=1&xe=2
Old German States stamps have a multitude of forgeries but most can be distinguished with the right reference material. Only very few absolutely require expertization and a certificate to ensure genuineness. (Not including postmarks - that's a whole other kettle of fish!)