Hello Chris,
According to your configuration it's for sure you're using a P410 controller or similar on this server. That controller will support higher disks (firmware will allow that so please check it's close to las version or latest). Actually I can see some 3TB SATA LFF drive options for this server in the quickspecs:
There are also some options for 6G but only in SAS drives, for SATA drives all seems to be 3G.
