If you buy the 8860 from the pfSense store and not the Netgate store, it comes with the port labels for pfSense and not Linux, and the default configuration set to match.
You can assign them in any order you like after pfSense is configured, but FreeBSD and pfSense will probe them as (reading left to right): igb1, igb0, igb2, igb3, igb4, igb5