That picture looks like a later type casting which has been ground down with two non standard thread inserts in evidence. On a couple of boxes to hand, the flat face of the mounting is near as dammit level with the lowest point on the gearbox shell underside....you can estimate how much is missing. With this amended, good chance footrest mount will be fine.
Top Picture...early box, sandcast texture, mountings stand proud.
Middle Picture Later die cast finish ? mounting bosses have a flared web to the underside of the shell.
Dimensionally they are identical and interchange over all model years.
Finally mounting height compared to shell underside.
Swarfy.