I believe they are a 50 year commemorative promotion. I think they should be stamped 37-87 which would suggest they were produced by Remington in 1987 or 88.
I remember seeing them at DU dinners back then.
They certainly are collectable and I would think would be worth about $10 or maybe more per cartridge.
Yes, that's all very accurate Patrick. I have them for sale on a gun forum that I am on for considerably less than that. I would take almost any reasonable offer, but wont split them up. We shall see what happens, if I end up keeping them they are still cool.