How often do SANS curriculum change? GCIA Specifically

in GIAC
I took the training in 2014, and i still have the books. I wanted to jump back into my books and create an index off the materials I have. And try to pass off that rather than paying for the course again. Will course material from 2014 be relevant to 2017 testing material? Thank you.
Comments
What I would do is study your materials you currently possess, create an index and purchase one practice exam and see how you do. This way you can see if the material you have is good enough to pass the current exam material. If you do well, then you can purchase an exam challenge.
There must someone here that has taken the course, and paid for extend there certification, they should be able to give you a good idea how much the material changes every four years.