Yes, early bay has a different more robust bar as the gearbox has only one mounting at the nose cone, late Bays have one in the nose cone, two small rubber bushes on top of the bellhousing and the engine bar. Also the engine mountings are different.
Abel
You might have to bite the bullet Sandy, these ave always been difficult to find as buses coming in often have these missing.
Once you think you've found what your after, go to see it or ask questions about it, couple of points to bear in mind are the holes that the bolt pass through to attach to,the engine, if they have not been tightened right they can go oval, also, on the inner side of the holes there should be a sleeve on each hole , I have seen these missing so you either have to have these remade or use a bug spacer, they can too have rust at the lower edges as it is hollow.
How desperate are you and have you considered the USA to find one.
Hope this helps