The P180 has been through a few different design mods over it's life - not necessarily tied to the B version (it used to have a vga duct in it as well).
As mentioned above, starting back in Feb. some time, P180(B) cases started shipping with all the P182 mods (WC grommets, different pass-through hole/cover between upper and lower sections, mb tray raised a bit + some slots to pass cables up the back, tri-cool fan switches mounted externally for top/rear fans, etc).
But keep in mind that while all new P180(B) cases might now be made with these changes, there may still be some of the older stock laying around at some stores, so it could still be a crap-shoot, depending on where you buy from.
I bought my P180 back on March 1st from Newegg and got the new changes, but I haven't looked to see if anyone has gotten an old style one from there since then. I'd say it's a pretty good gamble (from Newegg, at least).