Not all guitar brands use date stamps, but if you find one, you have your answer.
Look for the brand name decal on the guitar's headstock.
The year of manufacture is determined the same way for the Swamp Ash Special.
This can help when you are researching serial numbers.
This information is often written on the headstock or truss rod cover.
After the year prefix, these models us a code digit of "9", indicating a set-neck model bass.
The serial number will be located on the back of the headstock.