Did not remove break off tab on electrical outlets replaced
If the outlets test correctly and are functioning as intended then you should leave the break off tabs alone.

The break off tabs are there so that you can power the top and bottom outlets differently.  Most commonly so that you can have one of the outlets on a switch.  A less common and generally inadvisable reason is so that you can have each outlet on a different circuit.  

If you aren't trying to do either of these things then leave the tabs intact.  Older outlets often don't have break off tabs.  The only thing I would check to make sure of is that your outlet is rated to handle the amperage of the circuit.