Bad luck, that sucks. I’ve broken both of my collar bones, and done the Mega a few times too.
Looking back at my diary last time I broke my collar bone I did it on Dec 28th skiing, had it operated on Jan 8th, and was back on the slopes again on the 21st Feb, so 6 weeks later, but I felt I could have gone back a couple of weeks before that if I was very careful. Skiing is a bit easier on the shoulders than biking, but you’ve got 7-8 weeks so you should be in better shape. The trouble will be how scared you will (rightfully) be of falling on it again.
If you’re anything like me I think you’ll be able to go out there and ride the course, but I don’t think you’ll feel like you want to ‘race’ it. When I went back skiing it wasn’t for another month that I felt comfortable enough to risk falling on it again and so ski anywhere near my limits. I think you’ll be able to get down it ok, but it’ll be at 80% pace being very wary of people overtaking you and walking the tech bits. If you were going to trundle down at the back for the experience and walk those bits anyway you’ll have a good time. If you had hopes of qualifying for the main race you might find it a bit frustrating.