I looked on Revell's website, as they have a listing of instruction manuals in pdf form, however didn't see that one (which is strange as it is a current kit still available).
Try e-mailing Revell's customer service and they will either e-mail you a copy in pdf form (if they have it) or just put one in the mail for you. Just tell them it was a new kit, still sealed, but that it had no instruction manual.