"hunky-dory" < Sc. "unco dour" ?

[Benjamin Zimmer]

Reading another thread's discussion of "hunky", I was inspired to check
out newspaperarchive's early cites for "hunky-dory" and found this:

       Evening Gazette (Port Jervis,  N.Y.), August 4, 1870
       The slang expression of "hunky dory" is Scotch, and is a
       synonym of the Latin "non compos."  He is "unco dour in
       the uptak," is the full expression.

Has anyone run across this purported etymology before?  I've heard the
Japanese "Honcho dori" theory, but this Scots derivation is a new one.  I
take it the Scots expression would be glossed as "very stubborn on the
uptake", though "non compos" obviously suggests a graver mental condition.
 This would seem to be precisely the opposite of the sense of "hunky-dory"
as it emerged in the 1860s ('satisfactory, in good condition').

I've found some examples of "unco dour" in 19th-century Scots texts,
though none followed by "...in the uptak":

http://www.scotstext.org/makars/p_hay_hunter/chaipter_19.asp
James Inwick: Ploughman and Elder by P Hay Hunter;
Oliphant Anderson & Ferrier (Edinburgh and London) 1894, 1895, 1900
It wis nae uise speakin til him, an advisin him to come hame wi us, for
the drink wis in his heid, an it made him unco dour.

http://name.umdl.umich.edu/abk3684
Noetes ambrosianae. By Christopher North. (Prof. John Wilson.)
Selected, edited & arranged by John Skelton.
N.Y., J. B. Alden [pref. 1876]
The flunkeys - as we weel ca'd them, sir - a contumelious nickname, which
that unco dour and somewhat stupit radical in the Westminster would try to
make himsel believe he invented ower again, when the impident plagiary
changed it - as he did the ither day - into "Lackey."

http://cdl.library.cornell.edu/cgi-bin/moa/moa-cgi?notisid=ABR0102-0051-12
The Living age,  Volume 51, Issue 654, p. 640
December 6, 1856
A WELCOME TO AULD AGE.
BY MISS HAMILTON.
Ye winna promise! och! ye're unco' dour,
Sae hard to manage and sae cold and sour.


--Ben Zimmer