No
smith and Wesson (smith & Wesson) and Sig-Sauer
Smith and Wesson 500
I purchased a used Smith & Wesson 4013 for $350.00
N
Nothing.
The Model 57/657
100-225 USD
357CTG means that particular handgun is chambered for the 357 magnum cartridge.
Probably the Smith & Wesson Hand Ejector series of revolvers. In all of the models, and the copies of the models by other makers, there have been more of these made than any other handgun. It has been in production roughly 115 years.
100-345 or so
Probably an inspector/assembly mark.
100-225 USD