Concluding Follow-Up to Genba vs. Gemba?

I've spent a good amount of time with my teacher this week and I asked him about the Genba vs. Gemba question. Which is it?

He told me that "they are the same." Basically, because the "n" & "m" are indistinguishable in writing, they are the same. However, sometimes he told me that he would hear genba and then other times he would hear gemba.

Essentially, they mean the same thing and he told me that the only proof I would ever have is if I went to Japan and listened to Japanese managers talk! He did say that the same problem sometimes applies to genbutsu vs. gembutsu, etc.

In the meantime, you say tomato and I'll say tomato! Either way, it means "actual place".