Comparing Lrc catalog with Lr catalog

A few years ago, I moved from what I now believe is known as Lightroom Classic (Lrc) to what I now believe is known as Lightroom (Lr).

I kept Lrc on my PC.

I am now at the point where I think I should remove Lrc from my computer but don’t want to run the risk of removing any photos that are not in Lr.

I opened Lrc today and it advised me to update the catalog from Lightroom Catalog-3-3 to 3-3v10 which I did.

I noticed that there are 67687 photos in this (Lrc) catalog whereas in my Lr there are only 55,618 photos.

I suspect I may have carried out a purge on the Lrc catalog at the time of the change so do not want to have to do that again if I simply re-write the present Lrc over the existing Lr catalog (assuming I can do that). Additionally, I have identified that there are images (duplicated) in the Lrc catalog that are in the Lr catalog that were taken after I stopped using Lrc. How I managed to do that, I don’t know!

I would welcome any constructive advice.