All Macbooks claim to have the accelerometer, so it should work. If not, the sensitivity values are clearly marked in the script.

My Macbook pro retina does not have an accelerometer.

The acceleromenter was built into the MacBooks in order to protect the hard drives. I guess it makes sense that after moving to SSD the sensor has been taken out.

Yeah - it makes sense to me. I wasn't sure but I tried a few apps that are supposed to use it and looked for it in my system information and I didn't see it. (I'm really new to using a mac)