You need to get a letter on it from S&W. That bbl length is not to common and greatly affects value. If not original, then it depends on overall condition. Without a better description or knowing if the bbl is original the range can go from a few hundred to multiple thousands of USD.
The one screw basically.
The Smith and Wesson model 27-2 denotes that there was a second engineering change to the original model 27.The second change indicates that Smith and Wesson changed the cylinder stop,and eliminated the trigger guard screw.
It's only called a 5 screw if it has 5 screws
No tirggerguard screw is the main one.
Probably a Model 66
Via the screw.
Count the number of screws on the frame.
The Smith and Wesson model 18-2 had the cylinder stop changed,and the trigger guard screw deleted,The model 18-3 had the relocation of the rear sight leaf screw,and the model 18-4 change was the gas ring was moved from the yoke to the cylinder.The model 18-2 change was done in 1962,the model 18-3 in 1967,and the model 18-4 in 1977.
It was simply called the ".357 Magnum." More commonly known as the "Post-War Pre-Model 27." Your gun is a very early four-screw, made in 1956. sales@countrygunsmith.net
prices for the model 36 varies. I would estimate $450 - $550
Loosen the screw on the forearm push up on the screw and the barrel will pull out
IF a factory 5"and IF 98 percent 1800 or so. If you have the box, tool kit, papers, etc. it might make 2K