Hi Spch, I have taken my AVO apart but can only find one thing that looks like a serial number and that appears on the meter display itself. So the meter is a Model 8 MK 111 and the serial No is 6xxxx-B67.
I also have another AVO meter which is an ELECTRONIC AVOMETER Model No EA 113 and the serial No is 5xxx.
I do use the Model 8 for alignment but prefere to use my Fluke for most other measurements. Regards Brian.