Yes, it did have a retrorocket
The official NASA book on the Ranger series is online here:
http://history.nasa.gov/SP-4210/pages/Cover.htm
As I said, maybe someday someone will recreate the Ranger 3-5 mission to see if
it could have worked.
This would also serve a practical value, as a private space company could land
seismometers and other instruments on the Moon for science at relatively inexpensive
prices.
This might also be done for the other worlds, as we really need active seismology stations
on Venus and Mars, for example.