You are right siyaram...there is no FIFO concept with USCIS.
I did my stamping at Arlington VA, on May 05 2004 and still waiting for the card. Whereas in some cases stamping done in July mid (almost 2 months after my date), started receiving their cards.
My LUD is May 14 and no change afterwards.
After seeing the following message in USCIS web-site,
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"If you were granted permanent resident status or entered the U.S. with an immigrant visa more than 60 days ago and have not received your first permanent resident card, please call 1-800-375-5283"
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I called the helpdesk and informed them that it’s more than 90 days and I am still waiting for my card. They asked me “did you get any welcome notice from VSC” and I said no. They collected some info from me (Like A#, name and address) and told me that they are going to initiate an inquiry on my case status. I know very well that I am going to get a standard reply from VSC, which is not going to give any clear idea of what is going on.