I'm having trouble understanding your approach. If you're looking for a copy that's as close as possible to the original, why do this kind of thing?
I'm not talking about the repair (if done right), but about the .info files.
If the dates were wrong, the files have probably been altered.
So changing the date of the files won't bring them back to their original states!?
Also, .info files are linked to the creation of each disk, so referring to another disk doesn't make sense, unless of course they both come from the same root. Of course, these files can be copied and transferred from one disk to another, but this remains very random.
All this to say that we're moving away from the original spirit of the topic : "Original Workbench (and related)
disks preservation - Checksums required"
I agree with you that finding an unmodified original is much more difficult than it first appears.
Lynk recently delivered an interesting copy with very little alteration :
.info > altered
rootblock > altered with diskcopy
.../Collection/Various/Lynk's Stuff/AAA Collections/Nathan/Nathan Disk 13.adf