Options for restoration
The need for restoring NLO files depends partly on the deferred deletion interval. If the restore is happening from a snapshot that's within the interval (for example, the interval is 30 days, and the NSF is being restored from last week's backup) it's not possible for any of the NLOs to have been deleted yet, so there shouldn't be a need to restore any NLOs. If the NSF being restored is older than the interval (for example, the interval is 30 days, but the NSF being restored is from 3 months ago), it's possible that some of the NLOs have been deleted, and would need to be restored.
Some of this also depends on what the reason for the restore is. If it's a catastrophic failure, you should restore the NSF(s) and run tell daosmgr listnlo missing filename.nsf to get a list of all of the NLOs needed to make it whole again. That list should then be fed into the restore utility to restore those NLOs as well.
If it's just a matter of getting a single document with attachments back, you don't really need everything to be made whole to access just that one set of attachments. In the spirit of “Work smarter not harder,” you can restore the NSF, and then attempt to access the desired document (and attachments, if any) and finally deal with any missing NLOs that are mentioned during that operation. If there aren't any attachments on the document, there's no other work to be done. If there are attachments, the NLOs may still be there, so it's worth trying to access them before doing anything else. If any are missing, you'll get a console message that mentions the name of the NLO, at which point you can restore only what you need.