My Dad bought me my first new reel mower - a 14" model 45 with black chaincase and handle nameplate. I was a teenager.
I found this black finish very nice and a brilliant contrast to 'Kirby orange'.
I guess folks do not reproduce it because no one has offered advice as to how to reproduce it!
For me, it was not 'hammertone', but more of the crazed finish I would see on old typewriters.
Yours is the first credible attempt at this - and it has brought back old memories. That finish must have taken a lot of thought before you found a 'wrinkle' finish - in a can!