I wouldn’t assume a change in the sticker also represents a change in hardware. For example, I have the initial release of the M5StickC (no copper nuts, which are actually copper mounting screw holes), red 5V IN on the sticker, and no “RTC” label on the sticker. However, my device actually has a functional RTC inside. So adding the RTC label on the sticker doesn’t mean they revisioned the hardware and added the RTC. It was always there.
I also cannot assume that the M5stack documentation is accurate 🤣. I think they make little revisions over time and don’t always communicate or document what was done.