This is v.timely - I've been hacking round the doc trying to bring all the implications of NOLOGGING together. Perhaps someone can help me with this:

NOLOGGING will only avoid writing log entries for "bulk" operations: Direct Load to Table (SQL or SQL*Loader), CTAS, Move Table, Create Index, Rebuild Index, (plus some similar operations for partitions).

So if an object has the NOLOGGING attribute, but only "normal" DML has executed against it (i.e. none of the above), all the entries exist in the log files to permit recovery.

Can such an object be restored & recovered?
Can Oracle know if there are changes for which the log entries are missing (none in this case)?
What is the status of the object if restored & recovered? (e.g. is an index USABLE?)