NA Panasonic radio code long shot!

Morning all. 

I have a 91 NA Eunos and have also now got an origional (also 91 but from a different Eunos) Panasonic double din stereo, however I’m missing the code to unlock it. What are my chances???



Don’t think the Jap Panasonics were coded, only US spec were.

From the US Miata enthusiast site: