True, but I don't really consider them pockets, because they were used for a specific item, in that case the Type I phaser.
Real pockets: you can put different things in it. Like the ENTERPRISE uniforms. Or Beverly's coat.
Given the amount of technobabble in some series, they'd probably not refer to them as 'pockets' but as 'general purpose diminutive object retention space technology', or some such term.