B1/B2 Visa

I am an IMG from Pakistan who recently graduated and am about to start my housejob in July. I am done Step 1 and have my Step 2 scheduled for August. I also have a visa interview scheduled for September. My step 2 report is expected to be issued before the visa interview. Is it recommended to go for the interview without an observership letter? Or should I delay the interview till I have one? The problem is that the next interview date is after the housejob ends (after July 2027), and I plan to go for observerships as soon as the housejob ends, so that I can apply for the next cycle.