Yep, that's it.
Well, not really. Although, that is certainly the biggest difference. Some other differences are:
- The Xylophone is thought to be from Africa while it is believed the Glock is German.
- The Glockenspiel has a higher pitch than the Xylophone.
- Generally, the Glock has a smaller range than the Xylophone.
- With the above in mind, the Xylophone is larger than the Glock.