The nodes that appear in Manage > Nodes are the same that appear in the "DetectionIP" field of the data. If you look up a node in the node details dashboard in Ops Center, it does try to search on that IP address to provide more details and historical data.
Do the events in LEM have the information you're looking for in them? Or, does the syslog data have this information but LEM doesn't? It might help to see an example of the syslog event and the LEM event you're looking at to see the difference.