I've seen that 1927 mentioned on ttffonline.com, but it makes no sense if football was definitely being played before that, and other sources for example the match programme vs England say otherwise.
Here is the old Trinidad flag used up to 1958.
the motto on the emblem reads "She is content to make treaties and unite peoples." in Latin.
But I see no reason why a picture would be fake just because they used the full union jack.
I don't think Boyd was still playing in 1908 - he's dressed in a suit in that photo, not in the player's uniform.