Allwood:
You have a .38 Military & Police Model of 1905 4th Change manufactured between 1915 & 1919, with 1915 or 1916 being likely. The .38 M&P is the ancestor of todays Model 10 revolver. Your gun lacks the internal hammer block safety introduced during World War II. If dropped it could fire, so leave the chamber under the hammer empty. It was manufactured before heat treatment of cylinders was introduced, so stick to standard velocity lead ammo only, no PlusP, +P+, jacketed or semi jacketed ammo. The sites will be calibrated to the 158 grain lead round nose load.
Value is not high as several million M&Ps were made, say $250 to $350 in good to very good condition.
Almond27:
Your Model 66-1 Combat Magnum Stainless was manufactured in 1978 or 1979. Serial range for those years was 25K0001 to 56K9999 so 1979 seems likely.
alrutzz:
The 686-4 was manufactured between 1993 & 1997. From the pic I think your gun is a seven shot 686 Plus. These were introduced in 1995.
Product code 104277 was the six inch barrelled "Rusty Wallace" with an RWC serial prefix. This was a special run for Lew Horton, the only pic I found on the web was on Lew Horton's site and it appeared to be unported.