It looks like they are just thread neck tied jigs with some kind of tail material with flash in it. I have never known just what that skirt material is.
These I probably bought over 20 years ago and they have-not been made in many years. However I love them and thankful to have a good many left.
Also like the Nickel plated heads. I believe the next generation they made had rattle heads and I never got any of them, but was disappointed these couldn't be had any longer.
Skip