Ok thanks everyone for the assistance and advising.

Factory guns with beavertail forends have a different barrel forend loop/short rib arrangement which is one piece. And the forend iron is different. It is longer and beefed up in the front to accept a long reinforcement bolt that goes into the front of the forend.

These features were determined to be necessary for the abuse that a gun can see in the situations that a beavertail forend was commonly used in. IE: Trap, Skeet and competitive target shooting. Without these reinforcement features issues can arise from that high volume shooting.

Now... realistically, for a hunting gun that will see normal use, there is no reason that you cannot have a beavertail forend made for your gun utilizing the original splinter iron. Without modifying the gun or the barrels. And the original splinter wood could be put back on it at any time in the future.