The period was certainly one full of different loyalties in Scotland.

Anne was the last qualifying (ie Protestant) Stewart and had failed to produce any surviving heirs. No less than eighteen pregnancies had produced either stillborn children, or ones that died in infancy apart from William, Duke of Gloucester who died aged only 11.

Only the Act of Union in 1707 had brought Scotland officially into accepting the Hanoverian succession and it still wasn't a popular prospect.

Both Montrose and Argyll were supporters of it however and both were to be showered with honours in later life. At the time the film is set both were also only in their thirties (which you couldn't, even charitably, claim for Hurt and Keir).

So simply enjoy the film for what it is, not for an accurate historical account!