I am no expert, but I have absolutely no doubt that your answer is, yes!
From the tenth to the twentieth centuries, every legal document however formal had to be drafted, engrossed and copied by hand, and even while they were still in Norman French or Latin absolutely every common word had standard abbreviations, (e.g. "o" for "of", as in John-o-Groats ) which I find nowadays make reading Latin rather tiresome!
Originally the Gaelic word which we write as "Mac" meant simply "(son) of" so that Hamish the son of Donald who lived at Conchra might well be known as Hamish Mac Donald, or Big Hamish, or Hamish of Conchra, or if he were big and grand enough just Conchra. He would always regard himself as Of the Rae clan, or as a loyal follower Of The Rae if there were a chief "The Rae", and except for local purposes a clerk would need to classify him as such . A general clan name is also useful if a mother did not know the father- and bastards are very fairly treated by the Scots law of arms. (In Scotland many married ladies have always kept their own surnames without adopting their husbands, until now the fashion has come back again).
Once successive generation were all using the same surname, the particle is a useless formality and many clans just dropped it entirely. Indeed, most of our venerable forbears were illiterate well after then and would not know or care how anyone spelt any part of their names. English clerks indicted the accomplice to the plot against Lord Cochrane as M'Rae, and the Seaforth mutineers as "the wild.Magraws" , and you equally have Macrae, Cree, Rea, McRae, Macraw, and Ray.
There were no dictionaries of 'correct' spelling when Dr Johnson visited Kintail with Boswell (and none of the Macraes spoke English either). Until Victorian times many alternative spellings were legitimate amongst the literate, and a few obsolescent ones still are: for example shew and show, feint and faint; as well as the (often more authentic ) national variations such as color, or auld.
There is one branch of the clan in the East, two in the Wester Ross, and others scattered across the world by the Clearances and/or HM Forces. Once people learnt to read they would naturally tend to assume permanently whichever version their local minister or father happened to be using when he taught them to read, which has some advantage in differentiating between the thousands of our clan at any one time called Alexander, or John, etc.
Names, like all words, continue to evolve with the generations, so we have a MacRae-Gilstrap presiding over the Conchra branch. Also by 1715 it might be foolish for a Highlander outside his mountains to draw attention to his background, and in Kirkcaldy my family just used Rae by 1790; my grandfather born in 1880 was given the forename Burnett, and adopted it for all his children born from 1910: so his descendents are Burnett Raes, and the Lyon Court will matriculate them as such.
For over eight hundred years, cousin, we are all still MacRaes!
Reply posted by : Jeremy Burnett Rae