Interchangeable parts 1969 and 1961

I have a 1969 18 hp outboard that has a broken adjusting lever and shaft assembly. The flange is broken that the shift lever mounts to. I found a 1961 18 hp Johnson that appears to have the same adjusting lever and shaft assembly, before I pay to have the '61 disassembled I need to know if the parts are interchangeable. I was given these part numbers by a repair shop that said neither part is available anymore, it is possible that they are incorrect. If the part is not available do you think it is possible to weld/braze the flange back on to the shaft?

1969 18hp Evinrude 1961 18hp Johnson
Model Number 18902B Model Number FD 15
Part Number 379794 Part Number 377581

Thanks for any information that you provide.

Dan