IPSec VPN configuration

Is there any other way, than certificates, to authenticate a remote FC VPN client. I want to restrict access to only FCs, that are authorized by the FG 100D unit.

I want to avoid any scenarios, of a remote employee downloading the FC, and configuring (if he have the psk) the FC to connect to the VPN.

VPN sessions should only be established from company owned laptops with FC installed.

Thanks