The template uses inside the network interfaces discovery rules {$NET.IF.IFNAME.MATCHES} macro which is set to ^em[0-9]+$, this way it will identify only "em" interfaces, but those in FreeBSD are only those using the "Intel(R) PRO/1000 Gigabit Ethernet adapter driver", other interfaces will have different names, depending on the driver used, i.e. bce, ix, etc. probably too many to list and as FreeBSD adds new NICs more will be added.