Normally it should say E for empty if it rewound on most electric film cameras.
First: If the film is not rewound you should be fine. Your roll will end at an odd time.
Second: Many newer cameras will not fire if the film isn't loaded, or has been rewound. With mechanical cameras that didn't have this safeguard you could feel the film tension. (Lots of event photographers would 'dry fire' 50 shots or so to get people used to having him around, and lose their self consciousness about the camera dude)
Third: When all else fails, read the manual.
But check it. Look at the info display. Check with the manual. Does it say anything about rewound film in the camera? You might also get a quicker response from a forum for that particular make/model.
Physical check: Go into a dark room. Basement closet works well. Bathroom with no window. Note that it has to be truly dark. Room lights outside the room should be dark. Open the camera back, and feel if the film is still on the takeup spool. If it's not, then it was rewound. Take for processing. I it's still on the takeup spool, shoot off the rest of the roll. If your room was truly dark, you will be fine.
Sometimes when you run out of battery mid shot, the frame at that point will be seriously overexposed. Enough to wreck the image on either side too. You may have lost the shot before dead battery and the shot after. Otherwise you should be fine.
You probably want to experiment some with this so you know what the behaviour is.