Fiji battle hammer

[Helleri]

It looks like the color and sheen is uneven which is a good sign. But outside of that there isn't much more you can tell about patination from images. And ultimately the age of a patina is not necessarily indicative of the age of a piece. At any point in changing hands from owner to owner it could have been too aggressively cleaned or even refinished. So a patina can be partially or completely destroyed and rebuilt several times during a pieces lifespan.

And comparing patina doesn't help much because different items (no matter how similar) tend to see radically different treatment through out their life (i.e. temperature and humidity ranges they are kept in, degree of handling, chemicals they are exposed to etc.)

While this is all more or less true for most patination. It is especially true for anything made of wood wherein the patina is mostly made of dust from the air (which has become invested in oils that form on the surface from treatment, handling, and the wood itself, and is caked on) as apposed to oxidization, such as with metal patina, which tends to be more durable.