I had a Gina come in with some stem rot...

The seller is replacing it, but I am gonna try and save it. So I chopped it below the rot but there appeared to be some brown still between the core and the outer layer, so I took a couple other cuts but it still remains. Took the outer layer off to expose the "brown" stuff..

Well I stopped cutting because I am running out of the "Gina" scion...

Do you think I should be concerned about the "brown" stuff? I am really hoping it's not rot that has ran throughout the stem. BTW that's cinnamon on top of the cut in the last pic. Thanks!