請教PIJIANG老師, J1 TRANFERED TO F1, F1 VISA questions

請教PIJIANG老師, I arrived in US in J1 and application to F1 from J1 was approved last month. Now, I need go back to China for 4 weeks and I will go to Visa interview at US Consulate in ChongDu, China.
I have a question for you:
1, When I applied the tranfer from J1 to F1, I sent a I-20 with starting date 9/14/09 to USCIS, then the USCIS requested a new I-20 on 9/18/09 since the starting date was passed, a new I-20 sent, the application approved. And USCIS sent me back the new I-20 with approval stamp on it, but USCIS didn't send me back the first I-20. At the coming visa interview, is that enough if I only present the IO the new I-20 the with approval stamp? or do I need a new I-20 again since there is already a approval stamp on the I-20?
2, Also, at the interview, do I need to present the copy of tranfer application file which I sent to USCIS?
Thank you very much!