BMW announced that the previous-generation 5-series (E39 model) would have AWD but they never put it on. Honestly, I really doubt it. Although AWD is certainly a nice all-weather convenience, BMW is obsessed with RWD the way Audi is obsessed with Quattro AWD.
If I actually knew otherwise, I would say "possibly", but I really haven't heard/read/seen anything regarding an AWD 5-series so I highly doubt it.
If you're worried about a BMW in the snow, if you get a good set of snow tires for the winter, it will do fine with good, careful driving.