I went there at around 6:30am and there was a looooooooonnng line(300 people minimum were ahead of me),however right after they open at 7:00am, the security guard goes around asking the purpose of your visit and if it is for passport stamping he will ask you to get into another line after looking at your approval notice, there were around 5 people in front of me in this other line.
After you go through the security screening etc., you will be asked to stand in line 'A' and there was nobody there. You walk into one of the 'A' line counters where the officer checks to see if you have the relevant documents:
1. The original I-485 approval ( the one that goes to your attorney)
2. Passport
3. Copy of some form of ID ( copy of your Driver's license and/or copy of your first few pages of your passport with the relevant information like name, address etc.), I took both
4. ADIT style photographs
and then he gives you a token#, wait for your token number to be called. The IIO at this counter will take your original approval notice, scribble something on it , make a photocopy of it and give you the copy, collect your photographs, ask you to sign on the form for ordering your green card, stamp your passport which would be valid for a year.
You get out after that. I reached there at 6:30am , stood in the line, went in at 7:05am ( 5-minutes after they opened) and got out at 7:30am. It was a breeze.
Even though I wasn't asked for any of the other documents, I took my EAD,AP originals & I-485 receipts.
Good luck!!