I watch the repro market fairly close but not as much as some. So, take my opinion for just that. I think the B's are all over priced. When I purchased my first in the mid 80s you could buy a B for just a bit more than a D. For some reason the dealers now seem to think they are golden. Nice guns but not worth the $10k+ some are asking.
The D is a nice gun but nothing special. The price is pretty strong I think. Selling the fact that it is supposedly unfired. Lots of 2 barrel sets used but in good shape for quite a bit less, especially 12's
Keep looking. Perhaps
http://parkerguns.org/forums/showthread.php?t=29859