内详，不知为何不统一。我用的也是公司雇的办案无数的律师事务所

http://www.visajourney.com/faq/k1k2visa-aos.html#6.2.1

On the adjustment of status forms, there is a box for the visa number. This is the red number printed on the K-1, not the visa control number. I know this because the interviewer went over the forms in front of us, and crossed out what I wrote in there (the visa control number) and replaced it with the red number.(Note: this is on the lower right side, under the "expiry date". It is not the long number written along the bottom edge of the visa.)