yes they are the same dock. the d2 or d2g will fit in the dock with the extended battery and it is possible to have a case on and still use the dock. I'm not saying all cases will fir, but most of the ones i tried at verizon do, you just have to remove another mounting plate. I cannot speak for new ones like the otterbox yet
Yes - I believe it is the same sku for D2 and D2g. I use it on a daily basis and I find it very well designed. Better than original droid (much easier to dock/undock phone - you can do easily with one hand now). Interestingly - my dock came with adapter bracket for old droid (1) as well. Not that old droid doesn't fit just fine even with the D2 bracket installed. Best of all - you don't have to connect/disconnect the power plug every time you dock/undock the phone.
I use mine with vent adapter from a Garmin unit instead the provided suction cup arm. (Ball diameter is the same on Moto and Garmin). Suction cup mount puts phone too far from comfortable reach/view on some vehicles. Vent adapter works great for me.
Thanks for the help guys... I'm buying my dad one after his old phone sells on ebay (Curve 8530, not that old, but he wanted a new phone) and he has a D2G that I rooted, debloated, and wifi tether'd so he can cancel his aircard. Just gonna grab one off amazon with a rapid charger for $31.00, appreciate it.