morrowjg,
I can see why you want it fixed, as it wont fit right around the tangs, and have a wide crack at the front, and at both sides of them. If that doesn't fit correctly, it could lead to the stock cracking or splitting. This is generally what causes it on all doubles, except its really caused by age and shrinkage, though box lock actions are generally less prone to do it.
The only thing that I can think of, that you might be able to do, is bend those in, using oil and heat. I'm not sure if heat alone will do it. This would be the same process as stock bending, but your trying to pull the tangs inward, instead of bend the grip.
There are a few videos on stock bending at YouTube, showing them do it correctly. You would need to modify it, like you have with the clamp, and will still have to refinish this, as the method will destroy any finish.