Did logical positivists consider subjective statements such as "I like this cake" verifiable and therefore meaningful? Or did they consider that verificationism doesn't apply to claims of knowledge by acquaintance, and that these claims are therefore meaningful even if not objectively verifiable?
It would depend on whether their working definition of to "like" was an objective or subjective one.
If you define it in a Skinnerian behaviourist kind of way, as observably drawn to it on repeated occasions and showing particular responses such as smiling and calming down, then yes the logical positivist regards the claim as verifiable.
But if you define it in an experiential kind of way, as "Don't you tell me what I like, I know what I like and that's that", then no the claim becomes unverifiable and therefore meaningless.
The problem is of course in reaching a verifiable determination of which definition is the objectively correct one.