Yep, in contact with the wort that long, but we don't get isomerization until it reaches 175° though.
Edit to add: And once at 175°, the contribution to bitterness is less effecient because the wort still isn't fully diluted. At least in my case anyway. I really haven't put much thought into it, and I'm not really well versed on the chemistry side of it, so I'm sure there's many factors at play with FWH vs. waiting until full volume and starting a 60 min bittering addition.