Am I the only one that had to click on the link to find out WTH a "ghost gun" is? Hell,MY first thought was it was a gun from the Ghost Buster movie.
Now that I know,I STILL don't know what is wrong with owning one,or how it could be illegal to own one. I don't THINK serial numbers were even required on guns until after the 60's. Yeah,MOST guns have them,but they were mostly for inventory control means,not feral registrations. Hell,I have at least 1 double barrel 12 gauge shot gun with no serial numbers on it. IIRC,it was made in the early 1900's,and bought new by my grandfather.
I may even have another one. It doesn't have hammers,but was given to me when I was around 8 years old. Duck hunted with it for years before I stopped hunting. May be an Iver Johnson,but I can't remember for sure. Haven't seen the damn thing in years.