I did not call USCIS. But I ask my lawyer to write them a inquiry letter on 10/2006. Then I got second fingprint notice 2 weeks later, and I485 RFE 11/2006. The inquiry letter might expedite the process.
Reviewing my experience, the GC counts on
40% your backgroud + 20% lawyer's polishing + 40% luckiness (I would say I encounter a very picky and lazy immigration officer).
Anyway this is over! Best wishes to everyone in this forum good luck and get GC soon!