I would argue that it's common sense to at least make a point in time copy, to... IDK, a USB drive? Before trying to implement a new source/control system.

Just plug in an external drive, or a thumb drive, copy/paste, unplug it, then proceed with testing.

I don't see how anyone who values their time and effort could do any less.

As for the files, undelete is a thing, and it shouldn't be hard to do.