either open or sealed trnscripts is fine. neither is preferred over the other they both fullfill the same purpose.
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Application filled out by - Myself (feeling like a bad ass lawyer, haha)
App Sent: 8/15/2012 USCIS Dallas Lockbox USPS overnighted that baby fast! Received: 8/16
I-797c received on 8/27 Biometric appointment on 9/17 (done on 9/13)
APPROVED OCT 14