All pre-1964 versions of this model have some extra retained value, even if only for parts, due to condition.
At some point, in the last half of the 1940's, the hammer was changed from checkered to serrated, around 1948, I believe. Close to the time that the forearm was shortened, which I think happened just prior to 1950.
If your model 94 is a pre-64 version, I suggest that you leave the hammer in its worn condition. Honest wear detracts much less value than nearly all attempts at restoration, like reblueing, etc. Exceptions, perhaps, would be a rifle returned to the Winchester factory for a re-blue or other alterations. Another exception might be a restoration done by Turnbull, due to a well known reputation.