One looks to be a (as you mentioned) a full retail version of System 7.x, the other looks like an upgrade version of System 7.x. One is obviously a wipe the disk and install a fresh new version, one is an upgrade from a previous operating system.
The reality is and was, that any version of System 7.x (upgrade or full retail) would allow you to do a fresh install without the need for existing Macintosh OS to be on the disk.
I suspect the difference is down to the way Apple marketed the product and the software license agreement for each product. The full retail install would have cost more than the upgrade version.
To all intents and purposes each package will install the same System 7.x version assuming they're both the same. One may be 7.0, one may be 7.1, it's hard to tell but I suspect both are 7.0.
Simplicity is the ultimate sophistication...Steve Jobs