My university doesn't send to anybody via courier or mail. Last time I had to collect it physically and then sent it to CES in the same sealed envelope. They don't even address it.I would say worth taking the chance. Best & Quickest way would be get your documents delivered to Truecopy and then go ahead with the digital processing, As it would save you a lot of time.
But I am not sure if Truecopy will accept sealed envelopes coming from you, They accept sealed envelopes from university directly. But u can call them and ask them, They are really helpful & they might accept it.