BitmapPalette::GetGreyPalette() missing an index?

Hi all, 

I’ve been writing some unit tests around bitmaps and colours, and when I went to write a unit test 
for BitmapPalette::GetGreyPalette(nNum) it seems to be missing index 0 for grey palettes that 
should have 16 entries...

https://opengrok.libreoffice.org/xref/core/vcl/source/gdi/bitmap.cxx#140 
<https://opengrok.libreoffice.org/xref/core/vcl/source/gdi/bitmap.cxx#140>

Obviously, this is fixable, but not sure if this should actually be done - would it cause issues 
elsewhere in the code? For instance, would this cause issues in existing documents?

Any advise would be greatly appreciated…

Chris