Shong,
I have tested on version 5.6.2 and 6.0 and each version has yielded the same result. The Internal and ExternalIDs are both visible for the record itself, but the parent record references (i.e. 'Company' on the contacts table return recordref strings that include neither the internal or external ID of the parent customer).
In NetSuite's CSV import utility the user can select either the parent record name internal ID or external ID when importing contacts. In talend, none of the aforementioned fields work in the output component.
Pulling a sample contact from the database will exemplify what I'm talking about. For any parent record reference, a strange string including an '@' symbol is returned as opposed to an internalID, externalID or parent record name.