Hi John,
Within Connect for Mobile, it is possible to select a single element in DWG file .
Generally the object property and the 3D element ID depends on the way the file is created in the authoring application.
If its ok with you , could you please share the file with our support team (connect-support@trimble.com) , so that we can try from our end and get back if there are any findings.
Regards
Darshan Kamat