The pair were initially left out of the team named by coach Vern Cotter and replaced by hooker Fraser Brown and lock Tim Swinson after they were banned for three weeks for making a dangerous tackle during the Pool B game against Samoa.
Scotland appealed and a ruling on Saturday dismissed the finding that Ford and Gray had committed a dangerous tackle because the opposing player had not been dropped or driven.
Cotter delayed naming his team until just over an hour before kickoff.
Scotland team:
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1-Alasdair Dickinson, 2-Ross Ford, 3-WP Nel, 4-Richie Gray, 5-Jonny Gray, 6-Blair Cowan, 7-John Hardie, 8-Dave Denton, 9-Greig Laidlaw (captain), 10-Finn Russell, 11-Tommy Seymour, 12-Pete Horne, 13-Mark Bennett, 14-Sean Maitland 15-Stuart Hogg.
Replacements: 16-Fraser Brown, 17-Gordon Reid, 18-Jon Welsh, 19-Tim Swinson, 20-Josh Strauss, 21-Henry Pyrgos, 22-Richie Vernon, 23-Sean Lamont.
(Reporting by Justin Palmer, editing by Mitch Phillips)
