Do you mean the BadgeGen "State Badge" for Gibraltar doesn't have "Diamond" written under the flag as you'd expect if you've found 100% of the states i.e. 1 of 1?
I have the Gibraltar badge which says when the mouse hovers over, that ProjectGC doesn't have enough information. However, I do have a badge for Cayman Islands (similarly a small British Overseas Territory like Gibraltar) which says I have 1 of 1 state so 100% and have the "Diamond" highest award. Which is a shame really, as we have several sizeable districts here with caches in all of them.
Jersey is also a micro-state and I have the "Sapphire" badge for finding 7 of 12 parishes on a small island.
Hopefully this would be a quick fix as I think Gibraltar isn't divided up into smaller areas for any purpose - it's only 2.5 sq mi!