My memory is that IE v1 was never widely released to the public.
The only place I ever saw it was on a MS documentation CD, and then only because a coworker was pointing at it and laughing about how terrible it was.
I notice it's up on oldversion.com though. I suspect he skipped it because setting up a IP-enabled Windows 3.11 system was more trouble than it would be worth.
Serious question, I thought it was IE 1, but now I feel like I missed something.
Edit: I'm sure he does, he explicitly mentions various performance issues with IE 1.0 several times, starting with a screenshot at about 1:30