It was an Experimental model made between 1970-1983. If you have the original box & paperwork & might be of higher value than other models made in the same time frame.
Check the butt.
No serial number provided. Serial # 426742
1980
No such serial number in Smith and Wesson data.
You can not tell the model number with just the serial number.
1974
1980
You will have to provide the serial number and a detailed description of the weapon.
Look on the butt of the revolver.
@1969
On the butt.
Impossible to answer without the serial number.