I'm considering purchasing a fox sterlingworth philadelphia gun. the price is 325. and the gun looks pretty good with one exception - the inside of both barrels are covered with spots. is this something that can typically be fixed without a great deal of cost or is it something that can be done without much difficulty. i realize this all depends on how deep the corrosion is but it doesn't appear to be too bad. I'd appreciate any help that can be provided.

Scott