HP test equipment serial numbers follow a defined structure.

From an early-1990s service manual:

In the form 1234A00123 ; the first four digits and the letter
are the serial number prefix. This prefix is the same for all
identical instruments; it changes only when a change is made to the
instrument. The last five digits (00123) form the suffix that is
unique to each instrument.

The first two digits of the serial number prefix indicate the year of the engineering release, which is the last major design change. Add 60 to these two digits.

The letter in the middle of the serial number indicates the country of manufacture:

• A = USA
• G = Germany
• J = Japan
• U = United Kingdom