Sony doesn't store the serial number in the industry-standard field EXIF:SerialNumber like every other camera manufacturer. So you should complain to Sony (which is even less likely to produce results than complaining to Adobe).
In the Cameras Settings can you change the first set of character that are used for the image File Name?
If you can change one, or both, of the cameras to name the images differently.
I did that when I had 2 Leica M8 cameras. One started with L1 and the other started with L2. Those cameras didn't Roll over the File naming until 99,000 images taken so I was fairly safe that i would replace those cameras before I reached that number of images taken.
But If I hadn't I would again change the File Naming to something different.