If provisioned by 3CX, Extension, Model, and MAC are in the export of users. Serial I don't think 3CX is aware of at any time, but the IP can be seen on the phones page if the phone has an active registration.
Exporting from the phones page is not a natively supported operation, but can be done if you do some digging in how that page displays data. If you do get it exported, you will have extension, model, mac, and IP for all connected phones, regardless of 3CX provisioning them.