There are discrepancies between the clarinet part and the piano score in earlier published versions, too. (The piano part is to be preferred as a source, as I argue below.)
There seems to be no reason why the metronome marks should not be read as Bernstein's, though the metronome marking of the beginning of the second movement was originally misprinted as quarter=69 instead of eighth=69.
There have been postings on the Klarinet list on the subject in the past; here are some of mine:
I have to say that I find the spellings of the transposition in that to be less natural than the ones in previous editions (mine is Witmark, 1943), though that may be a matter of my having become used to the previous ones.