We were there at the beginning of May with an 8:05 reservation for BOG. After we went through bag check we had to check in with a CM to confirm our reservation. Then they corralled us into a roped-off section with other people who had pre-park reservations. After that point I don't think the time of your reservation mattered as much as how far up you were in the "herd". They ended up letting us into the park about 7:50. I kind of got the impression that people were seated according to check-in order but I guess I can't really confirm that. My suggestion is to get to the park as early as you can and be at the front when they let the PPR people in.