I don't trust a damn word out of Flex's mouth. That book is full of bullshit lies. If you search for a poster named "Livewire" you can find a post he copied of mine, about all the stupid lies Flex made up. For one thing, Flex had a real liking for the number 100.
And think about it, why would Arnold be at NikeTown? Wouldn't Arnold be sent his own shoes? I doubt Arnold was just strolling through the mall, though possible. But I'm betting that this is just another out and out lie from Flex.