When Gramps will build the surnames list on the first time?

Hello.
I just see that after importing a gramps xml file into a new Family Tree (creation), gramps 5.2.x will not create the surnames list. I suppose that it is the common metadata stuff and that’s why I get a surnames list when I quit (save, end of session) the Family Tree. What will happen if we look at surnames (tools, gramplets, surname guessing) on the first run after a Gramps XML importation into a new Family Tree ?
regards,
Jérôme