Tink,
The first is definatly a lathe dog. Second piece to the right could be an adjutable stop. Third part over looks like the rest of the stop. The three right hand parts are clamps for Vee blocks. Looks like two different sizes also.
You said that the guy was a gun smith. I would think then any tools that you have may have been modified or purpose built for that application. I'm sure there are some interesting tools there.
I saw some large milling cutters in one of the posts. Looks like maybe there was large horizontal mill available to the orginal owner to the tools.
Nice find by the way and I'd keep all the tools. Shipping charges to the UK are to high and just not worth it to send to Canada. Now Eric coming down and steeling.........I mean collecting some.....maybe. See his lathe is to small for such large tooling.

So this winter when it gets to cold up here in new York I'll be down with the truck and trailer and relieve you af all that metal sracp.

Regards,
Bernd