Is the Rumpler C.IV C. (MFFA 2) supposed to be blue or purple? In the picture it is blue but the one i got is purple. I was wondering if the colors got messed up on mine or if the picture on the site is wrong. Even though it does look fine both ways.

 purple is the correct colour.  (Yes, believe it or not, that colour was actually used!)  Note, the one Albatross D-Va with the violet band in the camo on the upper wing.  

Sometimes in an effort to stretch out the paint, two or more colours would be mixed together in order to complete a paint scheme.  In some cases it was a pilot's personal choice of colour combinations. (The Central powers were somewhat lax in the paint colours of the individual aircraft)

In some cases, a Jasta commander would stipulate what colour or colours could be used.  For example.  Jasta 2 (Jasta Boelke) aircraft typically had an all white tail section or white elevator or rudder.  The individual pilots were allowed to colour their aircraft to suit their tastes up to the Tail section.

 Thats interesting, I was wondering why all of the central powers planes were so colorful and the triple entente planes were more uniform.