Etymology of Ghillie Brogue?

[Wandering Spark]

Does anyone know the etymology of the word 'ghillie' as it's used to refer to the style of brogue? I know it is commonly assumed to come from the Scottish Gaelic gillie meaning male attendant to a Highland chief or more recently, hunting guide, but I can't find a historical source for this claim. None of the Scottish dress history books I have checked use the word ghillie or gillie to refer to a type of shoe.

Interestingly, none of the 19th c. sources I've read call these shoes ghillie brogues either. In The Clans of the Scottish Highlands published 1845, Robert McIan's illustration for Chisholm has ghillie brogues; James Logan's description of them simply says, “The Brogs are of a pattern frequently worn by gentlemen.”
The Book of the Club of True Highlanders published in 1880 has an illustration of a ghillie brogue which the text simply refers to as a "modern bròg". Carmichael's 1894 glossary of Gaelic shoe terms does not mention ghillie brogues.

My inability to find historical uses of the term ghillie brogue makes me wonder if it's a relatively recent name. Does anyone know of any 19th c. texts that refer to shoes as ghillie brogues or ghillies?

Books Checked:
Old Irish and Highland Dress by H.F. McClintock, published 1943
History of highland dress by John Telfer Dunbar, published 1964
The costume of Scotland by John Telfer Dunbar, published 1981
A short history of the Scottish dress by Richard Manisty Demain Grange, published 1967
Scottish National Dictionary here

Carmichael's 1894 glossary is in this article: https://doi.org/10.9750/PSAS.028.136.150