2nd time 24 bit remasters - can anything be possibly gained?

well isn't there always the chance that they found better master tapes?

the quality of a remaster depends really only on the quality of the mastering engineer. different people with different equipment in different studios can master the same mix a thousand different ways. it's very likely a new remaster of something will sound 'better' than an old remaster just because the modern engineer is working from the same paradigm as a modern listener, but whether a newer remaster is objectively 'better' is obviously unanswerable. the number of bits has very little to do with it; i think some studios are running 32 bit now but their results can sound better or worse than someone working on 16. the difference in accuracy to the original tape between 16 and 24 bit is really unnoticeable, especially where mastering is concerned, because there is no mixing being done, no dithering being done, and so the 2-channel audio is converted to 24 bit, processed, and then converted right back to 16 bit for the cd.

the short answer is pretty much no, unless the individual who did the first remaster did a shitty job, not unlikely