Hi,
The 41xx nodes have by default 4 disks, the 43xx nodes 8 disks.
There is no license, it is not possible to add disks, even if there are slots available. This is due to the fact that it is a DL360 server...
If you add the disks, probably it will work (if you extend raid groups on RAID controller level etc) but it will definitely NOT be supported by HPE. So this will be on your own responsibility...