Stamping in Dallas
No appointment needed. I went to Dallas location at around 10 AM and got out by 2 PM. There was slow down in processing during lunch hours. I suggest you go early at around 7-8 AM.
All you need is you approval notice (Courtesy copy is enough), existing EAD/AP docs, I94, Passports, Photographs, any valid H1 papers.
That's all.
Good Luck.