I wouldn't do it. I would pull the barrel pin and see if it can be tightened just a hair to get the sight up to center and still get the barrel pin back in. You might have to do a little more work if the barrel is up dead solid on the frame now, like face the shoulder back a couple thousandths to get room to tighten the barrel a few degrees. If you have to do that your barrel/cylinder gap is going to tighten up and may need to be adjusted, less than about .004" is problematic.
You need an action wrench to do any of the above. If you are only going to do this gun and maybe a few more you can make one out of hardwood. You need to fit the hardwood to the frame of the gun, so that it fits very well, then you clamp the hardwood in the vise jaws holding the gun frame dead solid and preventing you from bending it. Don't take a chance either, the frame on a revolver is VERY easy to bend and it takes a master to straighten one afterwards.
You should call S&W first, they very well might fix it for free if you ask them to. They do it quite a lot. That is your safest bet and where I would start.
