There are quit a few more sources than just that book which back up Romney. Go to http://thepage.time.com/romney-campaign-on-george-romney-and-dr-martin-luther-king-jr/
Even Time Magazine is now backing up Romney.
They quote the book? Come on, not this ____ again. Papers at that time say there was two separate marches on different days. This proves nothing.
by
Todd Spangler, Detroit Free Press ( 1d 23h ago)
...Free Press archives, however, showed no record of King marching in Grosse Pointe in 1963 or of then-governor Romney taking part in King's historic march down Woodward Avenue in June of that year. George Romney told the Free Press at the time that he didn't take part because it was on a Sunday and he avoided public appearances on the Sabbath because of his religion.
Romney did participate in a civil rights march protesting housing bias in Grosse Pointe just six days after the King march. According to the Free Press account, however, King was not there.