You do need to get there early
We went on February 5, got there at about 8:45pm, they only had one quota left and told us to come back to get another one. Since my spouse and I both need one. So we went on the 6th, at about the same time, because it was snowing, they still had quota for us.
My advise is if get there early enough, you should be able to get one. I don't think you need to get there at 5am, they don't open until 7am. Of course, it might depend on how many people on that day are applying for the iEAD. Be prepared to spend whole day there, however, if you are one of the earliest, you might be able to get yours at about 10:30am. They are so unpredictable.