Yeah, you couldn't give them away back in the day....folks really missed out. Due to poorly constructed bullets of the time and gunwriters shooting it hunched over the bench and getting nailed by the recoil, the gun/cartridge got a bad rep. Recoil is no problem at all when you sit up and mine shoots very small groups. I love the slightly more hefty barrel.
You are a lucky man on all accounts, finding those rifles/cartridges. The case of factory 356 Win. is worth a small fortune today. Even back in the early 90's it was already 25 bucks a box, and now I would think much more pricey. Except in one instance, I have not seen factory ammo on the shelves, nor seen it offered for sale for a number of years. I have a few 250 gr. factories left that I keep for Elk or Bear, but load my own. The brass I believe is still available though I've been stocked pretty well for years. You can make 356 Win. from 444 Marlin using Redding form and trim dies, if brass ever dries up.