Awsome! That solved it. The version I have is actually more complete with several missing menu ID definitions, but the make entry in addindata was not updated to match the increased make structure. Nice catch. I guess I have been staring too long at it to spot the size difference..
I can now say with confidence that I have the most up to date radasm header files for both masm and goasm. I have tested it and I can access all the members beyond the make item now.
Huge thanks for tracking that down, William.