No It doesn't. There is no pre-empt feature. when the new router comes online, he sets the DR/BDR addresses to 0.0.0.0. If the current DR dies, then the BDR will become the DR. and if there is no BDR a new election takes place then the new DR with the higher priority would be elected as the DR.
The reason is because, all routers in an area form full adjaceny with the DR/BDR and if the new router becomes the DR, we can't tear down the current DR adjacency and try to establish it with the new router as it would cause network downtime.
IF you have additional OSPF questions, refer to the documentation or the tech tips
http://www.cisco.com/warp/customer/104/index.shtml
