Moving to United States on DV visa and opened envelope supposed to give customs. Will I still be allowed in?

I have booked my flight to New York for three weeks time from Australia where I have won a Diveristy Visa in the lottery and have noticed in the instructions to hand over my sealed envelope to customs on arrival. I have mistakenly already opened this envelope and am hoping I am still be able to p through customs on arrival. To get this envelope replaced involves flying to Sydney return for approx $500+ (the closest consulate office) and possibly paying for my American airfare again, given the processing/wait times at the consulate. Would I be able to get through with my opened envelope containing all my required doents?