I can not speak on the authenticity of your imported data when switching an integration as that would be the xenforo import script.
As I tell anybody we have a script called userfix which might help you but that requires that a username exists in your forum for the EXACT
username that is in your gallery photos or comments tables. We can not guarantee you would be 100% successful when switching an integration as any realignment is only as good as the data that can be found to update it with. Say if you use userfix and the username is JohnB in your gallery and we try and grab a userid based off that username and its not found nothing is going to be updated.
The style we show is as I said above. Lets disect it some here. It is a simple if else clause in xenforo.php
Content visible to verified customers only.
$numstyle is the style_id field in the xenforo user table. $default style is the option in your xenforo option table for the defaultStyleid option_id field.
So what that code says is if the user has a default style id set in there user database table meaning it is not 0 then we load that style number otherwise the default style one set in xenforo is shown.
So I would suggest you see what data is in the actual tables because the style shown on the gallery for any user is going to be the style they have in there settings and if not it will be the xenforo default one.
I applied an indent fix to the 8.03 build.