Steve,
The dimensions stayed the same from the 2A through the CJ5. When you set up your new bracket in the former location, get it as level as you can. Left to right is more critical than forward to aft, but try your best to get it level in both directions. On my 2A, the crossmember was rotten on both frame rails. The center was good. Me being cheap, I cut both ends off and took some scrap pipe and fit them to the center section. The replacement tube for a 2A is marketed as the same as an MB or GPW war jeep, to which it is, almost. The difference is that the WWII jeeps had the bell crank mounted on the front axle, instead of the frame. A drivability issue comes with that configuration because you end up having terrible bump steer from being mounted on the axle. When the 2A was designed, that was probably one of the first things that was changed. Long story short, the reproduction replacement parts that are out there for the early models do not come with a bell crank mount, so that's why the mounts have become available.
Here is some semi useful information on the bell crank through some other forums;
http://www.willysmjeeps.com/v2/modul...ewtopic&t=8544