Scottish equivalent of "Smith"

[Nick the DSM]

Isn't Smith from clan Gow??

[O'Callaghan]

Isn't Smith from clan Gow??

One is a translation of the other, i.e. Smith = Gow, but there is a Smith tartan in any case. Sportkilt sell Smith kilts. I must admit the title confuses me, as the original post is all about Harbison, not Smith.