The trick will be having a flat, somewhat trued, surface to mount the new gas block on. The gas port landings are standardized (for the most part) in size and the areas in between are not.
If it's a not contoured or non tapered bull barrel, you "might" be OK.
This might be a cheaper solution...if the new hole can't be sealed to the gas block, you have a new metal baton, or Tact-tic-Cool single shot. Just sayin!
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=407097582 
