This is suggestive that they're a separate item; but it could still be argued that maybe pauldrons are still incorporated with chest-pieces when present at all, but they aren't present on that chest piece (that armor set doesn't have pauldrons).
But at the bottom right corner of page 52, you can see that the character seems to be wearing a pauldron on his left shoulder and not his right, and more importantly, WHILE WEARING NO CUIRASS.
So I think that more-or-less logically concludes the matter; individual pauldrons are in.