Further sleuthing proved positive. Well not exactly. The truth is I was googling to see if there was a crossover between any Picaxe chips and the ATmega8, ATmega168 and ATmega328. I didn't get a positive hit in that regard but I did find an updated (V1.06k) version of the PDF.
This PDF cleared up some of my confusion when viewing the later schematic, like the two dead ended conductors labeled "Button" and other labeled "Serial". The V1.04K pdf that I uploaded yesterday does not address these but the V1.06K does. The conductor labeled Serial connected to an unused SerialOut/ADC3 leg that's used to test higher voltage Zeners and also provide a Voltmeter function that the older design lacks. These are 2 pin tests only and does not utilize the 1 2 3 inputs.
V1.06K also describes additional protective circuitry using a micro-relay to be used on the 1 2 3 inputs. The relay contacts short all three 1 2 3 inputs prior to pressing the Test button. It's purpose is to discharge caps. This is a must for many of our members that like to party (Marty) and feel smarter for it.

It will save us from those moments when we do something stupid and then hate ourselves afterward!

My guess is that Steve's and Dave's commercial model is based on the older V1.04K.
At this time the location of the latest (V1.06K) source code still alludes me but I'm still digging. It's supposed to be on SourceForge.org but they're currently down.
Chris