Upon inspecting islandsf's east island model, it came to notice that the North Point Mall used to have a proper roof, rather than the blue mess.
My theory is the final roof was used for the interior only, however they at some point for some reason swapped it out.
This is a recreation with the LOD roof as a base.
The textures I have applied and vertex colouring I have done may not be the best, however I did not have a whole lot to go on other than general colour scheme.
If people want to edit it themselves and perhaps come up with a better version, they can go right ahead.