I've gotten a quote from Mr. Turnbull for the restoration of an unrelated gun and can tell you that the cost of one of his restorations will far exceed the value of the vast majority of field-grade guns ever made, the majority of collectors will always prefer an original gun to a restored one, and I can't imagine that someone spent that kind of money to restore a field grade Smith unless it had sentimental value, if you're curious about its value put in in a no reserve auction and you'll get the exact amount of that its worth.