Yes, that is what it looks like, it is so that there is enough bandwidth. They work with 1Gb transceivers in Ethernet mode but not stacking mode.
I am having trouble stacking my new N1548 switches. I have changed the status on two fiber ports on each of two switches to be "stack" using "stack-port tengigabitethernet 1/0/3 stack" and added the "boot auto-update-sw" command on both. The "show switch stack-port" command shows te1/0/3 and 4 on both switches as "stack". Turned both of the switches off and inserted Dell sfp 1GB single mode tranceivers in te1/0/3 of one and te1/0/4 of the other. Rebooted one switch and inserted a single mode jumper. Booted the second switch and no link light on either switch, nor any console messages. What am I missing?
Stacking woes with N1548 switches