Hello, new guy here, don't know why it took so long to find this spot. I usually depend on my mentor but interested in more opinions.
I just got another Kai-Gunto that made me question the Seppa on both sides of the Tshuba and O seppa, because the color on finished side, was not "gold" as much as a pale almost mustard yellow color. Same piece on my other good but not as good sword, looks like most worn gold plated brass fittings do. Only thing I can attribute it to is not seeing light for a long time. The rest of the sword checks out .. al s/n matching, good file marks, etc. Will post more side by side comparison picture, see one on left. Just wondering.