Thank you for the photos!
Certainly milled with a ball-tipped end-mill! And this type of tool didn't exist in 19th century for sure! 20 century again for sure!
Those grooves couldn't have been made with a chisel. They start with an ample curvature an with a lesser depth because that's when the linear movement of the mill starts and there is most resistance after the initial starting hole, so there is less control over the tool.
Do yo have this blade? Is it elastic like steel should be, or bends easily?
