Hey Dave.
Like Sonic I also write the originals file name into a field with the metadata template on ingest.
But all may not be lost. Most of my cameras write a frame number in the exif information. When I shoot RAW plus JPEG the files get named IMG_FRAMENO.CR2 and IMG_FRAMENO.JPG. Your camera may use a different prefix (IMG_, DCSN, ....)
You can recreate the "original" name using the {frame} variable as the suffix in a renaming pattern "IMG_{frame}".
You can check out the theory before renaming by:
Right clicking on an image and select "Image Info" and see if the Frame # field is filled in. Check it on both a raw file and its corresponding JPG file.. They should be the same.
Not sure what your directory structure looks like but if the RAW files and JPEG files share a common parent directory you could open a contact sheet on the parent using the "Open folder and subfolders in a new Contact sheet". That will give you a single view with both the RAW and JPEF files. Then create a sort on the {frame} field. That should put the RAW image and the corresponding JPEG image next to each other.
Gary