The broadsides, 1840's Vocal melodies of Scotland etc. appear to be all the Charlie words.. not the mannered version we all know. Though I am going on a 1902 newspaper quoted version for that. So far the 1876 Christie's edition is the first with the verses we all know.. 'wee birdies sing' etc. The 1885 printed version is also the 'modern' one.

By the 1870's the 'you'll take the high road' element is known in several countries and used in Punch magazine, so had already entered popular culture, sometimes with it being Ben Lomond, rather than Loch Lomond, but not as far as I can see provably the 1876 printed version.

In 1890, Lady John Scott is still alive, and newspapers are featuring her for Annie Laurie .. saying that she had been asserting her authorship/composition in making alterations and additions to an old original, as they were culturally famous. If she had written Loch Lomond in its later famous form, I would have thought she would have claimed some part of the credit via a moan to the press.