Well, anything can happen really, so you can't say for sure. Typically, I've found that in general, when they ask for RPRF (especially if you haven't paid it up front) it's a pretty good sign. Also, in general, most of the rejections/refusals tend to happen at the time of the documents are reviewed early in the process. I wouldn't worry too much, to be honest - adopt a policy of "No News is Good News" and carry on with preparations.
If your application is being processed in Ottawa for sure up til this point, keep a special eye out in your inbox for the PPR e-mail. It's very easy to miss. My application was pretty much entirely processed in Ottawa, so they sent the PPR e-mail as an actual e-mail to my account as opposed to the usual form of communication which is via myCIC.