Indeed, although "glas" has a quite different meaning in Gaelic than the English grey, as you probably know.
The obscured mountain range is known in English as the Grey Corries.
Glas can mean grey-green or even plain green, as well as grey. This is most obvious in some placenames. Glas is green in both modern and old Irish which is how it probably got into the placenames.
Gaelic also views colours from a different frame of reference than English. Gaelic colours centre around blue-green and red-brown. I think other languages/cultures have similar (but different) frames of reference.
@seachaint much the same in GME. It's quite an old 'problem' too, I recall being taught English colours with Gaelic words (if that makes sense) and not the nuances of Gàidhlig colouration.
I didn't get to take art 'anns a' Ghàidhlig' in secondary school, so missed out on learning about it there too. Something I think should be used in modern art classes in Scotland and Ireland (and areas with interest)