Remember, your amp is newer than the newest component.
ifoundudating com - Dating fender cabinet
Since his early teens Leo Fender had an interest in electronics, and when he grew up, Leo made a career for himself fixing and building PA systems for musicians, opening his own shop in California.
Leo soon realised that amplifiers needed to be sturdy to withstand the life on the road, and decided to build his own, to care for the needs of travelling musicians such as his customers.
If three digits are present, the first digit would refer the units of the year i.e. If four digits are present, the first two digits refer to the year i.e. The last two digits would refer to the week of the year i.e.
("26" would mean the 26th week or approximately June).
There are other methods used to date "Silverface" amps, you will need to get the date codes from your speaker frame, tube chart or pots.