Given that Black Megatron is the correct size and the actual color of a real Walther P-35 it could prove more difficult to obtain than Masterpiece MP-5 Megtron.
I believe it's actually slightly smaller - but it's pretty close. At a glance - and and at the business end of the barrel - you wouldn't notice the difference. The laws are designed to make sure that people don't end up in that situation.