I had to look up the Stevens 94B. Good luck on that one. I know I live in an isolated area, but I've never even seen a US marked single shot that wasn't in a book. I was hard enough to find a blanket procurement 620. I never did find a really great example.
On the Ammo question; I have some of everything "for display purposes", I don't know that any of it is particularly rare or valuable. Mostly the kind of stuff you see at oldguns.net I never sprang for the mint packages which is okay given how they appear to deteriorate over time. Shrink wrapping helped.