I'm not an expert, but I understand chess well enough to know that if a person at that level is going to cheat, they can't just play their own game and then let the computer tell them what moves will save them. They have to use the computer throughout the whole game and slyly use a combination of their moves along with computer-suggested moves. Early moves that are off the mainline but suggested by a computer would provide an interesting and safe avenue for a cheater to get his opponent off their game.

So yes, IF he was cheating, he likely would have started cheating on move 1.