Workhorse: The Model 36 is only a 36-1 if it has the 3 inch heavy barrel, otherwise it would just be a model 36. Rcmodel is probably correct about the date, the Model 36 Chiefs Special serial range ran from 295000 in 1962 to 786544 in 1969. If the grips are original and have an uncheckered diamond around the grip screws then its from 1968 or earlier. If the grips are original and lack the diamond around the grip screws then 1968-69. Husker_Fan: Best I can give you is 1957 (serial no.125000) to 1962 (serial no. 295000) The flat latch continued until 1962. Miststamped guns are not that unusual, not to far back in this thread is a Bodyguard from the same era that hadn't been stamped with a model number. Of course, there is the possibility that the serial number has been restamped when the gun was refinished. I'll leave that to you to figure out. Have fun with your new toy.