Hi,
OK now how you have imported the 7.0 DC to 7.3 NWDS? my assumption would be using Import-->General-->Existing Project to Workspace in that you have located your _comp folder right.If so then is might have asked for Migrate the project to DC like components.If you came up to this you are correct. Then you should be able to build and deploy the DC if you have configured SAP EP Server details in NWDS.
Regards,
Srinivasan V