A copy from a piece of actual cookware can probably be as nice as the talents of the molder and/or pattern maker. I once had two Favorite (marked) No.4 popovers which were copied from a Griswold No.10 popover pan. The Favorites were about 1/8" shorter than the Griswold pans and of perfect quality. One of the Favorites showed clear ghost marks of a slanted GRISWOLD name on the center cup plus the other markings including a p/n 948. The other Favorite pans was every bit as well cast and matched exactly to the ghost pan but had no ghosts. I think it was made earlier and before the pattern (which was probably made using an original pan) had the filling in the original Griswold writing starting to wear.
It was probably more of the smaller foundries that made copies that may have been bottom gated. Many pans copied from another pan will have poor casting quality and many small defects. Others will be as good as the original pan. Marion and Wagner both used ERIE skillets or modified patterns to cast their own skillets and both are superb in quality but, here, we are talking about major makers.