If the ejectors are all intact, and you don't plan to lose them in the future, your Purbaugh tubes should prove satisfactory. However, they do not add value to your Browning. They would be a clue to you as well as any future buyer that the gun has been shot a lot. A seventies Superposed in average condition with Purbaugh tubes should be valued the same or a little less than a similar gun with no tubes. Test for salt wood.