WW1 GEW Mauser barrel band???

Are there different width rear barrel bands used on WW1 GEW, long barreled Mauser's?
I have an acquaintance in the UK that is trying to find the barrel bands for a WW1 GEW Mauser. The Mauser is strictly a wall hanger as it was literally dug up some where in France. The only markings that he can make out are 1916, and the letter D. He seems to think that he needs a band that is 20mm wide. He has a band that is 10mm. But he said it was too narrow.

Any comments or suggestions would be appreciated.