Well... I don't think we're talking about the same song. I also have the songbook you refer to, and yes, I can believe that song was written by a hack! The one I mean is the (infinitely more poetic and succinct) one that goes, "Cruel is the snow that sweeps Glencoe..., etc.," and is in the database.

(I sometimes think that everyone and his brother has either performed or recorded it.) The Corries, on "The Collection", attribute it to a pair of songwriters "MacLean-Duthart", and I've seen another attribution to a D. MacLean, with a copywrite symbol attached. That suggests to me that it hasn't been around long enough to have entered the public domain. Nothing I've seen, however, has said what the "D" stands for.

By the way anyone interested in the full account should get their hands on "Glencoe" by John Prebble. It was published by Penguin in the '60s, so it might be a bit hard to get, but I found it in Glasgow in 1990, so it's probably still available.