Ask: Materials for I-539

I see in the instructions for filing i-539 change status back to F1,  I need to submit Certificate of eligibility for Non-immigrant student issued by the school you attend - my old admission letter has long disappeared.  

Do I need to ask my shcool for another copy?  Anybody here done that before?  Should I just ask the Office of International Admissions to get me a copy?

Thanks!