Smith and Wesson made the model 686-3 from 1988-1992.
No
No
No
S&W did not make a model 4.
yes
No
No sn data.
One has been.
No. The Model 28 is a .357 Magnum.
With the serial number that you have provided,your Smith and Wesson model 28-2 Highway Patrolman was made in the year 1973.
Not available in the public domain.