Call INS to get a duplicate I-797

My wife applied for a H-1b visa in Beijing this summer. She didn't have copy of I-797 (top part and bottome part, she only has a copy of bottom part). I called INS and a very nice lady fax a duplicate I-797 to me in five minutes. Although it is indicated as duplicate, the visa officer accepted it without any problem. I don't think you need a original one anyone. Just my opinion.