What is the age and value of a Chicago Arms shotgun?

Chicago Arms Co was a trade name used by Hibbard, Spencer, and Bartlett on shotguns imported from (mostly) Belgium. The dates you have been given would be in the range for that company to have been the retailer, but I think too early for a slide action. In the condition you describe, it will be worth very little. If you wanted to buy one, you would probably have a hard time finding one for sale, but if you want to sell it you may have an even harder time finding an interested buyer.