Moving to a new forum (backup / restore)

[Road Rash Jr.]

Will the structure still be there from the new empty installed SMF ?

Yes it will, installation creates everything required for that table so you don't "need" the structure or content. It's provided and will contain all the default values.

[Illori]

yes it would be, you would also when done with the merge need to reset everyone to the default theme, which can be done in the admin panel.