There is no way for the sound provider to target individual speakers when split like this, so you will not have the rear channels coming from the rear speakers. They will just have the stereo sound duplicated.
In a sense you will have "surround sound" in that the sound will surround you, but it won't give you any spatial information, such as when playing a game, having the sound of action behind your character coming from the rear speakers.
If you are playing games, they will be aware that they are targeting a stereo only system and so shouldn't split the sound into fore and rear channels anyway.
From an audio perspective, I doubt the sensation would be any different to putting the stereo speakers to the exact right and left of your head. There isn't any additional sound information with the extra speakers.