I've got Case knives both with and without the brass liners. It's not uncommon, especially on older knives. And yes, those larger knives have pretty strong springs.

Be sure to wipe down the backspring occasionally if you're handling or using it, CV knives have CV springs as well. They take a beautiful patina after some use though.

I prefer CV, the Cases I regularly carry are all carbon steel. They take such an incredible edge.....