See my previous post, but there is really no rhyme or reason how, when, if parks "officially" open. In our experiences a couple of weeks ago, HS, MK, and AK were all open 45 minutes before official posted hours. What this means is that temp check opened and then the procession began through security, main gate and to wherever you were headed. In COVID times they're simply trying to keep things flowing and avoiding lines so I'm sure park operations has a say as to when the first step, temp checks actually opens.