If you can get a SCSI Drive from the first Mac Portable to read on a classic Mac, like a Plus, Mac II up to a Q700, you can. And without fancy cloning software.

Just format the second drive in the system you want it on (System 6 format I believe a portable uses), and then copy the folders & files from the first drive into a folder in the classic Mac, and then copy the folders and files from the folder in the folder on the classic Mac to the second drive.