I have thousands of DSLR slide scans with filenames in the format "Text-CameraFileNum-SequenceNo." SequenceNo is the original slide number. I would like images to display in original slide number order, and the only way to achieve this seems to be to move the sequence number to the front of the filename. If I try this within LR, a new sequence number is assigned, so I have both the wrong number and the wrong order. LR "knows" that SequenceNo is a LR assigned field, and is unwilling to treat it as text. I can move the existing sequence number to the front using Bulk Rename Utility, but then LR loses the files. I can regain them in LR using Import, Add but the whole process is rather cumbersome. Is there an easier way?
Yes, "sequence number" means a specific thing to LR. In your case, the data you have is not a sequence number, it is the slide number, which means nothing to LR.
However, in your case, there is a good chance that the Rename dialog will mistake your slide number for the "original file suffix".