You would also need to include the model of Smith and Wesson along with the serial number to get the correct answer to your question.
1980
No serial number provided.
No serial number provided.
No serial number provided.
No serial number = no way to answer.
Need the serial number
K 7981 smith&wesson
You will need to add the model of Smith and Wesson to your serial number to get the correct year of manufacture.
1978
y
THA7110
@1971