These particular ferrules are an attempt to get the sight somewhat on a perpendicular plane to the shooters line of sight, is, what creates the form. The acrylic is solid chunks of material, so there isn’t any limitation on how or what shape it is turned too. However, when working with this material, when turning, caution needs to be used, side stencil strength has its limits.
...on the second ? Doing the joint work is not an issue, getting the similar wood grain and natural color is a hill, then getting sheen/finish match starts another issue.
Tensile strength.