Yes you definitely have an early copy of the System there. So now we have the first known copy of the System to predate .85
The "Aternate Disk" is what the "Unknown Disk" was called originally, and appears throughout the first edition manual which had to be written and sent to press well before the final system was locked - obviously using this system or another early version. As a result Apple included this insert which corrects certain aspects of the manual, and this change in particular: http://homepage.mac.com/chinesemac/earlymacs/PDFs/032-0001.pdf
One thing I will point out is that the Finder on the Guided Tour Disk is labeled 1.0, but it is clearly quite different than the Finder on the original "1.0" System Disk, which is also labeled 1.0. From what I recall when I was snooping around in the Guided Tour's System and Finder, was that the Finder is pretty much responsible for things like the "Alternate Disk" icon, meaning that you should take the About the Finder reporting 1.0 on these disks with a grain of salt. Definitely check out this Pre-release Finder with ResEdit ... You may find yet another early version of the Finder as well.
As for using ResEdit, just start looking around the resources, and you'll get the hang of what's what. A lot of it is just code, but a lot of it will have the lines of code annotated, and of course there's the icons. But the only way to really tell if there are differences is to compare the resource sizes from one System and Finder to another. Once you find discrepancies in resource sizes, then you pretty much confirm you are looking at different versions, despite what About the Finder may report, and you have a starting point as to which resources deserve additional scrutiny.