If I scan the resource files from Logos 6 installation and use the scan command in Logos 4 (the comoputer cannot be upgraded to Windows 7) will they work?
It might work. To be more sure, You could copy just the files older than the Massive Update to a :\resources -folder & then scan.
As Unix indicated, newer files that were created to make use of recent L5/6 features probably won't - however, there's no 1:1 relation to your last change date, other than that L4 does not support "smart select" and therefore it might not be able to read the files affected by the massive update. If so, and since this was substantial, trying to scan might cost more time & effort than it saves in terms of download and indexing. Maybe someone from Logos will tell you more.
trying to scan might cost more time & effort than it saves in terms of download and indexing
As I understand it, scan doesn't save you any time indexing, it only saves time downloading. You still have to index the files that you scan. And I would agree that it might be more trouble than it's worth trying to figure out which resources will work with scan and which won't. Might be simpler just to let Logos 4 download everything and go get some work done on your Logos 6 installation on your other computer while you're waiting for it.
Scan (in Logos 4) will only take the files that are compatible with Logos 4. Any missing resources will then be downloaded by Logos 4.