What he wants to do is the functionally existing within LR today; alter capture date applied by the camera which is wrong. Again, after import, totally possible using the command outlined above.
You could copy your files to your computer with your file manager, and then use ExifGUI to batch change the capture date/time easily. Then import to LR.
I think the difference between this and the correction in LR after import is that ExifGUI changes the capture date in the Exif part of the metadata, whereas LR adds a new capture date in the XMP part of the metadata.
The LR method ends up with two different capture dates in the metadata; LR reads the Xmp one preferentially.
To avoid any confusion in future, I prefer to have the original Exif capture data altered, not another one added.
You can even use ExifGUI to alter the original Exif capture data AND the XMP capture date to the same value.