According to William Melven, who revised Stewart of Garth's regimental histories for Keltie's 'History of the Highlands' (1875) all the enlisted men were drafted into the 87th and 88th, after which the officers and recruited the regiment anew, under the command of James Johnstone of Westerhall. It is possible the regiment was only referred to as 'Johnstone's Highlanders' from that point on.
"Johnstone's Highlanders
ONE HUNDRED AND FIRST REGIMENT. 1760—1763.
This regiment, which consisted of five companies, of 5 sergeants and 105 rank and file each, was raised in the year 1760 by the following gentlemen, viz. Colin Graham of Drainie, James Cuthbert of Milncraigs, Peter Gordon of Knockespie, Ludovick Grant of the family of Rothiemurchus, and Robert Campbell, son of Ballivolin, who received captain's commissions.
After the companies were completed they assembled at Perth, and thence were marched to Newcastle, where they remained till near the end of the year 1761, when they were sent to Germany, to reinforce Keith's and Campbell's Highlanders. Their officers did not accompany them, but were ordered back to the Highlands to raise six additional companies of the same strength as the other five. This service was soon performed, 600 men having assembled at Perth in a few months. Major, afterwards Sir James Johnstone of Westerhall was appointed to the command of the corps, with the rank of major-commandant. The Major, Adjutant Macveah, and Sergeant-major Coxwell, were the only persons in the 101st regiment not Highlanders. Lieutenant-general Lord George Beauclerk reviewed the regiment at Perth in 1762, and declared that he had never seen a body of men in a more "efficient state, and better fitted to meet the enemy." They had, however, no opportunity of realizing the expectations formed of them, not having been called into active service. The regiment was reduced at Perth in August 1763."
Fifty years earlier, Stewart himself had expanded on the character of Major Johnstone's command in a highly complimentary fashion here: 'Sketches of the character, manners, and present state of the Highlanders of Scotland, with details of the military service of the Highland regiments' 3rd Ed. 1825 (Vol II)
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