How to check the Android version that the phone was running on before flashing it with SailfishOS

Is there a way to find out the version of Android that was installed on an Xperia 10III before flashing with Sailfish OS? I had a quick look but didn’t find anything.
For context I have 2 Xperias running Sailfish OS and one is behaving better than the other so I want to find out the exact build of Android that was installed on both phones before I flashed it with Sailfish OS.

As far as i know there are some partitions left over from flashing the binary blobs and SF.

But how, where, what and why, I can not tell you.

If you have two and are OK with erasing one of them, flash the latest Android version you can from this table The baseband version table