Metricbeat AWS module metricsets and exported fields

I have a question regarding exported fields of metricsets for the AWS metricbeat module, specifically if they all include some variation of a unique identifier.
For example the RDS module has an exported field aws.rds.db_instance.identifier which can uniquely identify metricbeat data to a specific RDS database thus enabling the option of filtering and possibly separating the data of each database to a different pipeline.
For other modules the documentation does not seem to indicate any such field in the exported fields such as ELB, Lambda...
So the question is does metricbeat data for all the grouped metricsets(RDS, ELB, EC2, Lambda...) contain a unique identifier on which the data can be filtered and separated (same question applies to grouped Filebeat filesets)?