Valvestate manufacture dates

[Gbc66]

Does anyone happen to know what date and year the valvestates were commenced?
I have just refurbished a mint 8040 and it has the date 21/05/91 on the QC sticker.
I always thought they started in 92.
Cheers
Gaz

 

[scozz]

Valvestates, 1991 to 2000,… AVTs, 2000 to 2007.

How To Date A Marshall Amp

This guide will help you decode the serial number and model number of your Marshall amp to finds its date of manufacture.

reverb.com

 

[Gbc66]

Ive got the exact date of manufacture 21/05/91
I curious to know if its near the start of manufacture of this amp model.