If you are asking about the "ridge" that runs through IGWT, that is caused by Die Deterioration and is quite common on Zincolns. It is also referred to as a Ridge Rim. It is not an error and not collectable, unfortunately. 
In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024

























