The Compete Peerage says that he did -- https://play.google.com/books/reader?id=KbIKAAAAYAAJ&pg=GBS.PA248&h...
Anyway, he married only one Margaret Montgomerie, not two, the other one should be merged, but they differ in the year of birth;
The one who seems has married two Margaret Montgomerie is John Stewart Earl of Lennox. If really one Margaret married both of them, it was the 2nd wife of the Earl of Lennox (born about 1451), while the one born about 1425 with marriage contract with the Earl in 1438 is the first wife.
https://www.clanmacfarlanegenealogy.info/genealogy/TNGWebsite/getpe...
http://www.thepeerage.com/p10921.htm#i109207
Two ladies named Margaret Montgomery are involved here:
(1) Margaret Montgomery, the daughter of Alexander, Master of Montgomery, who married, as his second wife, Alexander, first Lord Home.
https://archive.org/details/scotspeeragefoun03pauluoft/page/435/mod...
(2) Margaret Montgomery, eldest daughter of Alexander Montgomery, Lord of Ardrossan, who married John, first Earl of Lennox. This Margaret Montgomery was not of lawful age when she was contracted to marry John Stewart on 15 May 1438.
https://archive.org/details/scotspeeragefoun05pauluoft/page/349/mod...
https://archive.org/details/scotspeeragefoun03pauluoft/page/435/mod...
Alexander Montgomery, Lord of Ardrossan, is the same person as Alexander, first Lord Montgomery, which, if correct, would make him the father of Alexander, Master of Montgomery.
Mariota Home, Heiress of Landell
The book says he's the son of Mariota, daughter of Sir Robt. Lauder.
And that he married first, Mariota, daughter of (Unknown) Landals of Landals, Berwickshire.
But here we have the two Mariotas combined in a single profile.
And a search of this book finds no Janet Hay, his Geni mother. Janet Hay
I don't see any William Hay with daughter Janet who married Alexander Home either, in this book.
And I notice several serious inconsistencies in these Geni lines.