These are the currently documented APIs:

https://jazz.net/wiki/bin/view/Deployment/CLMProductAPILanding 

For ETM/RQM, there are several APIs, Reportable REST, OSLC, Module API, Server APIs.
The Reportable REST API allows to create/update ETM/RQM data.

Maybe you consider to understand what Items you want to deal with and then have a look at the data for exemplars that are archived. I would assume that "archived" is just some kind of attribute/flag data. Use appropriate APIs from the set I mention above and GET the archived data to confirm the difference between archived and not archived data.