Fire Caste Exemplar: You can add 1 to hit rolls in the shooting phase for other Tau Sept TX7 Hammerhead Gunships within 6".
The FAQ then removed the word "other" from this rule.
Pay very close attention to which words are in bold. Only the words "Tau Sept" are in bold, not the words "TX7 Hammerhead Gunship." This means "Tau Sept" is referencing a keyword, while "TX7 Hammerhead Gunship" is not. Longstrike thus buffs datasheets with the name TX7 Hammerhead Gunship which have the keyword "Tau Sept." Longstrike's actual name is "Longstrike's Gunship," and not "TX7 Hammerhead Gunship." Thus, he cannot buff himself.
I suspect the word "other" was removed in order to lessen confusion about the rule, when in reality it may only have made it more confusing. I bet they removed the word "other" because it implied he was a TX7 Hammerhead Gunship, when in reality he is not.