Buck,
That is a very nice example of the styled 25 you have there, I am sure you will soon have that one running and restored. Quite a heavy tractor on those solid cast iron wheels, I have ploughed a lot with mine and found sometimes on heavy ground the French and Hecht round spokes slip with three furrows behind, so can understand the idea of the additional weight of the cast wheels, better than just bolting wights onto the wheel.
I am fairly sure your tractor has had a manifold change during its working life, both unstyled green and styled red 25's have all the same manifold with elbow and vertical exhaust pipe set up, this is seen in all the various literature on those models and I must say this is the first 25 I have seen with the Wallis style manifold.
Let's see what all the other 25 owners think.
Malcolm.