new_day,
Just the sealed envelope fro your university (transcripts) would not suffice. You would also need to include the copy of your mark sheets and degree/diploma from your side and also good to include the Application Summary that is generated after making the payment online in WES website (This would have the reference number that would help them tie your documents to your application). Going by your assumption that you just need to send transcripts across to WES, in case if transcripts are directly sent by University, do we not send across anything. That is not true. We would still need to include a copy of the marksheet and degree/diploma from your side.