If you feel like digging further, cut the head off one and you will see the flash holes are drilled. Only a couple of high end manufacturers do that, one being Norma.
Keep in mind this is NOS brass, not equivalent to the new Browning ammo offering (crap) you see on shelves today. I think I bought my fist 100 pieces from them 20 years ago, and they probably had it for 30-40 years prior to that. The Metalverken they have us from the 60's-70's as well. Some may be a but tarnished bit clean up easy.
It's very good brass.
***and for Norma making Nosler brass, very few are made there, the Weatherby's are and a few other belted mags, standard common cartridges are definitely not and source probably varies from year to year.