Respondo a mi mismo. Incluyo resultado de dmesg:
[16306.357743] usb 2-1.8: Product: SAMSUNG_Android
[16306.357746] usb 2-1.8: Manufacturer: SAMSUNG
[16306.357748] usb 2-1.8: SerialNumber: 1000a3d0c165
[16306.357853] usb 2-1.8: configuration #3 chosen from 1 choice
[16306.358367] cdc_acm 2-1.8:3.0: This device cannot do calls on its own. It is not a modem.
[16306.358435] cdc_acm 2-1.8:3.0: ttyACM0: USB ACM device
[16306.359271] scsi11 : SCSI emulation for USB Mass Storage devices
[16306.359384] usb-storage: device found at 7
[16306.359386] usb-storage: waiting for device to settle before scanning
[16311.345223] usb-storage: device scan complete
[16311.346205] scsi 11:0:0:0: CD-ROM Android UMS CD-ROM 00 PQ: 0 ANSI: 2
[16311.347036] scsi 11:0:0:1: Direct-Access SAMSUNG GT-I9000 0000 PQ: 0 ANSI: 2
[16311.347906] scsi 11:0:0:2: Direct-Access SAMSUNG GT-I9000 Card PQ: 0 ANSI: 2
[16311.354183] sr1: scsi3-mmc drive: 0x/0x caddy
[16311.355195] sr 11:0:0:0: Attached scsi CD-ROM sr1
[16311.355743] sr 11:0:0:0: Attached scsi generic sg8 type 5
[16311.356365] sd 11:0:0:1: Attached scsi generic sg9 type 0
[16311.356745] sd 11:0:0:2: Attached scsi generic sg10 type 0
[16311.362927] sd 11:0:0:1: [sdh] Attached SCSI removable disk
[16311.363622] sd 11:0:0:2: [sdi] Attached SCSI removable disk
agustin@
aspirem3870-desktop ~ $
Por lo que creo que estan montado tanto sd interno como externo
Esto ha sido con depuración usb habilitada en SGS, pero no me permite visualizor contenidos con Nautilus