You will have to call S&W with the sn to find out.
@ 1964-5
@ 1976
With the serial number that you have provided,your Smith and Wesson model 28-2 Highway Patrolman was made in the year 1973.
The best that I can do is say that the smith and wesson model 28-2 was made by smith and wesson from 1961-1969.
1978
1975-1977
Between 1978 and 1980.
The smith and wesson model 28-1 was made in 1962. To date there is only 1 (one) example of the -1 variation known to exist, a 6"
Look on the back side of the wooden grips, the month and year should be stamped on one of them.
2200.00-2500.00
Smith & Wesson was founded in 1852.
The S&W Model 28 "The Highway Patrolman" was produced c. 1954 - 1986 with 8,427 manufactured the first year. There were several variations. The prefix of N was added in 1969. The numbers inside the yoke may help determine appx. yr. ...28 (1957), 28-1 (1960), 28-2 (1961) Hope this helps.