IMAP UID FETCH BODY.PEEK[] command response

I'm now developing a simple IMAP-client. To recieve message body I'm using command "UID FETCH message-UID BODY.PEEK[]". The question is can I be sure that one of the server responses on the command will be "* message-sequence-number FETCH (UID message-UID BODY[] message-body)"? Or should I be ready to recieve any possible FETCH response (like with message envelope)? I know that I can recieve message flag updates in form of "* message-sequence-number FETCH (FLAGS flags)", I just ignore it now.

Of cause, I've read the standard rfc3501, but did not find out the answer.