The exact same thing happened to me at the Sportsmans Warehouse in Brownsburg. They wanted to make a copy of my Indiana drivers license before they would sell me any ammo. When I asked why they said it was Company Policy.
I left the ammo at checkout and left.
It looks like a set for a Mossberg 500/590. If you want a stock set for a 930, take a look at Boyds. They sell hardwood stocks for the 930 series. In UN-checkered regular walnut they are about $200.