If it has no J prefix it would be about 1967 to 1969. If a J prefix it is 1976-1977
1962-1969
Sometime in the 1971/1972 time frame. You can call S&W and they will tell you when it left the factory.
@1972
75-76
Buy the serial number if applicable.
go to savage99.com/savage99 date.htm my sn was 36-516 as was manufactured in 1902
With the serial number to your Smith and Wesson model 36-1 being J562694,this indicates that it was manufactured between the years 1976-1977.
You will have to call S&W to find out.
Marlin- Mdl 80 with an adjustable trigger
All S&W revolvers I have seen are serially numbered on the butt of the frame. You may need to remove grips to see it. My Mdl 36 wears a set of Hogue rubber grips, and they cover the butt.
If manufactured prior to 1/1/1969 no serial number was required and if it was made later it must be clearly visible on the receiver. The Model 36 was made before serial numbes but the latest versions may have the assembly date code. http://www.histandard.info/PDF/Sears%20Rifles.pdf
Call S&W and they will tell you when it left the factory. It could have been made a week to a year before.