Yes, unless RIM were to lock down the PIN for use in the US, as has been rumored they might do, until the ATT version is offered here. There are a few posts about that on the forum here, not thoroughly substantiated, however.
Your TMo-Germany Bold will have a QWERTZ keyboard vs the English standard QWERTY keyboard, where the Z takes the place of the Y on the keyboard.
RIM doesn't block the PINs. Devices from Germany come unlocked out of the box, so there is no need to unlock them.
The attached picture shows the difference between QWERTZ (German) and QWERTY (English) keyboard layout. The Y and Z keys are switched and instead of the $ sign the German keyboard has a xxx8364; sign, but you are still able to type the $ sign as this key can be configured.