10gb ports (ports 49-50 ) are seperate ports because they are SFT+ ports, the 1 GIG ports 47-48 can be used at the same time but not as a lag.
Also note that if you have a copper link on port 47 or 48, that once a MGBIC is linked up, the copper port will drop.
The MGBIC can be inserted (without any issues) into the combo port without a connection