You apparently have a Colt 357. That was both the model name and the caliber.
The 357 was made from 1954 to 1961, with about 15,000 produced.
The 357 was intended to be Colt's premium revolver, bettered only by the super-premium Python.
The only known 5" models were nickel plated guns made for the Florida Highway Patrol. These will have FHP stamps on the frame.
If the gun is not a nickel FHP gun, the barrel has been cut down and value goes down.
Value depends on actual condition, with an FHP gun bringing higher prices due to the rarity.
Other factors are the type of hammer and whether it has original grips, especially Target grips.
A 357 from 1958 would have had either small Service grips, or the fully checkered Colt Target grips.
Fully checkered Colt Target grips themselves are worth in excess of $250.00 these days.
Hammers were the narrow Service hammer, or the Colt Target hammer.
Target grips and hammer add to the value.