Glencoe MacIan or Clan Johnstone?

[Franklin]

So...

I thought I had completed my genealogical studies last year when I gave my presentation to my family at our reunion. I had plenty of evidence that put the relatives of emigrant patriarch Daniel Johnson at the Battle of Sheriffmuir (1715). I had plenty of circumstantial evidence to link him to Johnstons of Caskieben. So-- I bought my son and I Johnston Modern kilts. They are awesome and we wore them to the Games in May. However, a cousin (who paid out the nose for several DNA tests) was contacted by Clan Donald in Scotland noting our DNA connection with Glencoe MacIans (Johnsons). I joined Clan Johnston/e in America last year with certainty. However, I had not renewed my membership this year as there is a mound of evidence that we are not in fact Johnstons but MacIans.

QUESTION: Is it improper to be part of a Clan to which we have no kin? MacIans were obviously a sept of Clan Donald so do I sell my kilt for the Glencoe Kilt? I think I'm talking myself into it as I write...