I don't believe so, but I'm not sure. The Falkland Islands weren't, and it's believed that even Hawaii would not be covered under the language of the treaty.

edit: Found this on /r/MapPorn

https://reddit.com/r/MapPorn/comments/ulb5mc/nato_article_5_coverage/

>That in turn, triggers Article 5 which

Article 5 does not get triggered automatically. And the treaty lays out conditions for invoking it by a country that has been attacked:

https://www.nato.int/cps/en/natohq/official_texts_17120.htm

>For the purpose of Article 5, an armed attack on one or more of the Parties is deemed to include an armed attack:

>on the territory of any of the Parties in Europe or North America, on the Algerian Departments of France 2, on the territory of Turkey or on the Islands under the jurisdiction of any of the Parties in the North Atlantic area north of the Tropic of Cancer;

>on the forces, vessels, or aircraft of any of the Parties, when in or over these territories or any other area in Europe in which occupation forces of any of the Parties were stationed on the date when the Treaty entered into force or the Mediterranean Sea or the North Atlantic area north of the Tropic of Cancer.

An attack on pipelines in international waters for example might not technically be accepted as a reason to invoke article 5.

https://www.theguardian.com/world/2006/jan/23/russia.georgia

>Georgia's president, Mikhail Saakashvili, accused Russia of sabotage and "outrageous blackmail" yesterday after explosions cut off gas supplies from his country's energy-rich neighbour.

>Two simultaneous explosions at 3am yesterday cut through both tubes of a gas pipeline just on the Russian side of the border with Georgia. Another blast struck an important electricity pylon nearby nine hours later. The three blasts left Georgia with limited supplies of Russian gas for heating. It also meant Georgia could only supply about 40% of the electricity demanded by its 3 million inhabitants in temperatures of -5C (23F).

>But Mr Saakashvili called the blasts "a serious act of sabotage on the part of Russia on Georgia's energy system". He told Reuters: "Basically what happened is totally outrageous and we are dealing with an outrageous blackmail by people who do not want to behave in a civilised way."

>Relations between Georgia and Russia have deteriorated considerably since Mr Saakashvili came to power after a pro-western "rose revolution", yet yesterday's recriminations marked a new low.

>The Kremlin has sought to tighten its control over the energy industry, and analysts suggest Russia intends to retain its influence over former Soviet states and beyond by manipulating the price and supply of oil and gas. It has doubled the cost of gas for Georgia but has frozen the price for its more loyal neighbour, Belarus.