Wolf ears stopped about 1960.
On many, not all, SCs had the back of the of the rear dropouts filed flat instead of being left in the original "rounded" state. Again, a stolen image from Stefan's collection to illustrate..
Ah! Now I see, you are referring to the extra "meat" in the back is removed from the original casting. Great point.
VeloBase.com - View Single Frame Part
My SC from ca 1971 has the rear dropouts filed down.