Yes, the Sparks Nugget character's name is "Last Chance Joe" (now moved to a Sparks historical society site).
I don't know if the Carson City character was named Sparky -- could be?

Comparing photos -- Bill's salt shaker looks more like Last Chance Joe, with both hands down.
By contrast, the Carson City character has one hand up and a gold miner's pan of gold.
Did Carson City's Nugget have a 3-dimensional character like Last Chance Joe, or just the neon sign outside?

Anyway, here's 4 photos for comparison:
Last Chance Joe sculpture (Sparks); Nugget building and sign (Carson City); CC Nugget matchbook; Bill's salt shaker on ebay.

I think the salt shaker looks more like Sparks Nugget "Last Chance Joe", with some changes to colors, etc.
With that, I'm done! It's just a salt shaker!