Over the years I've bought a number of editions of "The Man from Snowy River and Other Works" by A. B. Paterson. In one of them the tune is stated has being taken from a soldiers marching song from the time of Marlborough.

If that is true it would most likely be from the period 1702 - 1712. Mozart lived between 1756 and 1791.

I have heard Waltzing Matilda sung to three different tunes and do not know the one referred to in the notes mentioned above.