To be sure just hold up a magnet to it OR open one up from the top end and dissect the shell. Or you can just shot one against concrete and recover the shot.I assume you are not able to ask Dad about all this.
Reloads are spent shells that are made up NEW again using components to REMAKE the shell, like casing, primer, powder, wads, shots.The person that reloads his own shells have the liberty to adhere to factory recommendations or change some aspect of the shell, kind of custom make it.Just make sure the shells are the right lenght e.g. 2 3/4 inches 12 Ga. if that is you gun SPECS.