Your guess is as good as mine. I checked the Japanese Twitter-verse, and couldn't find anything especially revealing. Then again, I can't really read Japanese.
If his number scheme stays consistent, then this model should be the follow-up to the CW-L31, as the CW-L12 is the follow-up to the CW-L11.
The CW-L31 is a four-driver model, and was the previous flagship before the CW-L51.
The 'V' should be some kind of variant denotation, like the CW-L51a is to the CW-L51.
Basically, if all CW models are designated CW-L(x)(y)(z), then the model description should be (x+1) drivers, version (y), variant (z).
CW-L01: 1 driver, version 1, variant [default]
CW-L01P: 1 driver, version 1, variant 'P' (portable)
CW-L11: 2 driver, version 1, variant [default]
CW-L12: 2 driver, version 2, variant [default]
CW-L31: 4 driver, version 1, variant [default]
CW-L32: 4 driver (?), version 2 (?), variant [default]
CW-L32: 4 driver (?), version 2 (?), variant 'V' (Vocal? Vanity? Vermicelli? Veal? Vicissitudes?)
CW-L51: 6 driver, version 1, variant [default]
CW-L51a: 6 driver, version 1, variant 'a' (adjusted? anime? average_joe?)