LR does not preserve file creation date. Many Mac users have asked for that feature on LR -- see this topic in the official Adobe feedback forum: Lightroom: Changes creation date of image files | Photoshop Family Customer Community. Add your vote and opinion to make it (a little) more likely Adobe might implement that feature.
My own opinion, expressed in that thread, is that Adobe is unlikely to implement the feature. The photo industry has defined metadata fields for storing many different dates/times, and most photo apps ignore file creation date. On Windows, few apps make any attempt to preserve creation date, and on Mac, there are many apps and utilities that fail to preserve it, including Apple apps (much to the dismay of long-time Mac users who came to rely on the long-time Mac convention of preserved file creation dates). Thus, at this point Adobe has little incentive to provide the feature. But I'm always willing to be proved wrong!
Most likely you are looking at the wrong date.
The file creation date is the date that the individual file was created.
Sounds like you are interested in the image capture date, which is in the metadata.
The fact that the original file's creation date and the image capture date are the same (or within one second) should not be treated as anything more than coincidence.
Aha. I see what you're saying. Yes the Get Info window has the date/time of export. But I see if I re-import one of those recent exports, its metadata does give the original capture date. Thanks!
Yeah, it seemed pretty outrageous that, with everything these machines can do, the date that the photo was taken would be lost to the ages.