If your amp dosen’t have a date code, flip the amp upside-down and check the transformers, and speakers for their manufacturer codes.
If possible, open up the chassis and check a few of the pots’ and capacitors’ manufacturer codes.
There are several ways of identifying a manufacturer, or particular part number of a component in most audio gear that's been manufactured since the mid 1950s.
View the underside of the chassis (flashlight helps alot)look for the reverb driver trans.
Its in the middle of the 6 preamp tubes with the removable shields. For a black face, this transformer would have been made in 1964 during the 23 week (—423) The trick to this is they don’t renumber the decades.
The model type, or number, is sometimes stamped on the transformer frame, or bell, as well; for example 022798, telling us that this is the power transformer from a Fender Super Reverb.
There are several ways to determine when a Fender amp was produced.