These days it's really easy to accumulate synthetic memory material in the form of thousands of photos and videos. My kids are covered that way. The hard part is still having access to them a generation later. At least the sparse material from back then survives as fading photographs in a physical album. Not so sure about the flood of material accumulating on people's phones these days. Mine lives on reliable backups but I figure once I'm gone all that digital data will bit rot like everyone else's.
As for "same person"? Of course not. Both body and mind change over time as you accumulate life experiences, both good and bad. It's a continuum of change. I'd have quite a bit of stuff to tell my 30 year ago self. Don't know if he would listen.