Well, the fish itself looks right... I guess there could be several reasons why there is no A, a tourist might have asked for it to be signed while visiting the factory and maybe that is how they signed items that are not normally signed. There are one or two other examples like it on line. Also the signing conventions themselves may have been changed over time. The signature itself raises no 'red flags' for me, I would be happy with it if it were mine.
John