
Mark T. answered 03/14/19
Career nuclear engineer, professional instructor, Lightroom expert
I have a naming strategy for SEO that precludes this issue. For you the important thing would be to set up an import preset to automatically give new pictures a prefix before the number. that will set you straight in the future.
For your current problem at hand I would rename the current pictures with a prefix, like a year, month or something else. The rename tool is easy to figure out in LR.