For the campaign you choose which one is pre-installed and thus logo engraved on the back. Dualboot is worked on and they committed in a tweet and IGG comment to try having it ready when shipping starts.
Until that, manual reflash to Lineage/Ubports should be trivial to test the one out you did not order preflashed.

What i just assume is that the sfos port from Pro¹ should also work on Pro¹-X since only memories have been upgraded. Any more educated guess on that?