I agree with
@demographic, these are two Estwings I re- handled & used boiled Linseed oil on, it does darken the leather quite a bit but combined with burnishing makes a nice finish. Right one oiled, left one not, the colour lightens a little with time. An old image, they look better now with more oil & burnishing but both fairly dark.
Ahh, nice one.
You'll have spotted that the inner steel section has a date drop forged onto it.
I assume they don't change the date on the drop forging dies every day they start work so my guess is that the date is when the dies are made.
I have one with very loose washers that had a 1937 date on it and Estwing patented their hammer style in 1932 so it's an early one.
Then if you look at the side of the head where it meets the shaft, on yours its kind of a V shape and on mine its kind of squared off.
From looking on the internet I think* they stopped that head design in about 1960 as thats the latest I know of like that.
Not positive though and I'm not gonna take mine to bits to read the date on it.
Ignore the fact that the top one (old style thats squared off) has the straighter claws and bottom (new style head side with the V) has curved claws
Also the transition from the leather washers to the steel shaft on the newer hammers is more gentle. That means the last few washers are very weak and liable to breaking.
The older style of washer transition is more stepped and in my eyes anyway its stronger.