Re: What model 357 Colt is this?
It could be either a Colt .357 or a Trooper. Does it say "Colt .357" on the barrel? The Colt .357 was Colt's premium revolver in the 1950's before the Python hit the market. In fact, the Python is just a Colt .357 with a vent rib and a really nice blueing job. The original Trooper was a less-polished version on the same frame.
Your gun was made around 1958. The gun came from the factory with checkered wood grips. The white pearl grips are aftermarket. Hope this helps.