Concerning the Clan Gunn surname
'Surnames as we understand them today did not come into general use in the Highlands until the 17th century.'
Page 16 Margaret Maclaren of MacLaren's 'The Maclarens A History of Clan Labhran'.
But yet we are meant to believe that the surname Gunn originated from a man who died no later than 1240, in Norway, some three to four hundred years before surnames became fixed in the Highlands. It's just not possible. The surname Gunn has no Scandinavian / Orkney origin.
I have dealt with this issue many times, but thought I would add a new source.