There were real screwbacks...
Pieces of History out of AZ used to make a fairly decent looking reproduction screwback GAB about 15 years ago.. At first they fooled many. I'm not sure about this one,,it does look pretty good!

I have a couple hollow backs and maker marked badges I'll dig out eventually..

Here's anothet unmarked example:

DSCN1834.JPG (80.31 KB, 154 downloads)