Since you have the factory letter, you have all the general information about the Model 3, as well as the specifics on your revolver. What did the letter state as to the original finish - was it nickel or blued?
For me, a reissue barrel address does not add value. There were a total of 60,000 of this model manufactured, with 9000 Reissue and 13,500 Commercial production. The Russians with Cyrillic markings, even though the majority of those manufactured, command higher values.
An interesting note on valuing these guns can be seen when looking at the stated value of Second Model Russian Commercial guns. A total of 85,000 were manufactured, but only 6200 Commercial guns were built, yet the value in many gun books is lower than the main production guns for Russia. It is assumed, of course that there are few Russian contract guns surviving in the collector's market.
Jim Supica makes no comment on any value adder for commercial/reissue guns and estimates the following: Fine - $2000; VG - $1250; Good - $950. The Standard Catalog of S&W was printed in 2006, so a little out of date, but still an accurate source of information.
Hope this helps.