If the gun was contract engraved in Italy, the value is around $2500. If the 29-2 was engraved at S&W by an engraver on staff, add around a thousand dollars to the value. The style of engraving done by Italian contract engravers is easily recognized. S&W began contracting out engraving in the late 70s to make engraved guns more available to customers.
The values cited above are ballpark and will depend on the actual 29-2, the level of coverage (A, B, or C), finish (bright blue or nickel), etc.
Bill