They've bit but don't know their neck shine from Shinola
Reference to the phrase you don’t know shit from Shinola. Modern rappers don’t have very discerning tastes: they copied (bit) his style, but couldn’t tell it apart from Lil Wayne, so to speak. They don’t know their gold chains from Shinola.
Shinola was available in the early 20th century, so this line might hark to the many African American shoeshiners during the time of racial segregation, trading in their shoeshine for jewelry.
To help improve the meaning of these lyrics, visit "Figaro" by Madvillain Lyrics and leave a comment on the lyrics box