Like Dave said, there was no walnut until later. Even later thin neck/slim neck joint models from 1966 onward have mostly cherry finish althogh they are usually darker - but that is the darker mahogany used, and I think they changed something in the finishing procedure (can't remember exactly, but i think it was something with the grain filler that now got a washcoat before it was put on). Wasn't the walnut introduced by the time they got slotted headstocks?
Anyway yours is about '65 I guess - at least the wide controls put it before mid '65 but that bridge was introduced during '65. Looks stripped, a finish that faded/old i guess would be less smooth and more crackled. My '65 has original finish, it's somewhat orangey like yours but not 'dirty' around the worn spots. The dirty spots on yours looks (to me) like if they are on bare or stained wood, but who knows. Mine is sparkling red under the pickguard, so when you get it home you will see!
If the finish is just dull and unclean, just rince and buff it up. If it is indeed stripped, get it refinished. It's nothing good about an axe you can't clean, no matter how 'old' it looks..
Great find!