Thanks, I'll see if I can figure it out.
I believe this is what I need to do, then automate the procedure using Automator:
Preparation (locating and tagging the erronous files)
1) In the Finder, open a window, navigate to the root folder of where the files with the wrong creation dates are located, then perform a search with the needed criteria to find those files. This is what I used (first of all searching for "." as I assumed that would search for any file with an extension):
Be sure to search within that root folder (named "Err" in my test-example) and save the smart-search with a descriptive name (e.g. "ERR creation dates").
2) Since all the erronous creation-date images are now displayed all at once, tag them in the Finder (select all, right-click and click on "tags" in the pop-up menu. At the same time add a red color label.
3) In the Finder, open up another new window, navigate to the root folder of where the correct creation-date files are located, then perform a smart search for the files with the correct creation dates using this search criteria:
Ensure searching is performed within the correct folder ("OK" in this example) and save the search as a smart-search with a descriptive name (e.g. "OK creation dates").
4) As with the previous window, tag the OK files as well (e.g. "OK creation dates" and a green label)
That's the easy part done...

now that we've determined which files have the incorrect creation dates and which root folder contains the same files with the correct dates we need to figure out a way to actually replace them, so here's my analysis of that:
File replacing (ultimately done automatically in some way)
1) display ALL “error” files (wrong creation dates) in a Finder window root folder
2) display ALL “OK” files (correct creation dates) in another Finder window root folder (same structure as with the error files)
3) examine the entire file path of first “error” file
4) locate same file on “OK” drive with the exact same path as above, but on different drive
5) copy the “OK” file (correct creation date) over to equivalent “Error” folder, but first renaming the existing “error” file by adding “_error_creation_date” at the end of the filename,
then adding an “OK creation date” tag to copied file as well as an additional “green” color label.
This will ensure I can revert in case something goes wrong, and the replaced file will be clearly visible with its tag/label.
6) repeat procedure for second file, then third, fourth etc.
Does this seem correct? Have I missed anything?