Consider the following statements regarding the Greek (Gandhara) and Mathura Schools of Art:

1. The Gandhara school of art was heavily influenced by Hellenistic styles, while the Mathura school was more indigenous in nature.

2. Gandhara sculptures were primarily made of red sandstone, whereas Mathura sculptures used grey schist.

3. Mathura school of art exclusively sculpted Hindu deities, while the Gandhara school was associated with Buddhist iconography.

4. Buddha images in the Gandhara school show wavy hair, draped robes, and realistic expressions, whereas the Mathura school portrayed Buddha with a more spiritualistic appearance.

How many of the above statements are correct?