This came from the home of a very heavy smoker. The brown marks are just dirt and nicotine which are very easily removed.

I purchased this at a Goodwill store, and after doing a little research found that some of these banks can be pretty valuable, but I was unable to find a picture of mine exactly.  The bank is in working order, all of the mechanisms seems to work as they are supposed to.  The gun is cocked, a coin is placed on the barrel, and when a button is pushed the man "shoots" the coin into the tree, and a bear pops out of the top.  I have several pictures from various angles below.