Here is a pic showing the
in-book reading stats (it is from an older firmware version, but the latest firmware shows essentially the same information just with a different layout). AFAIK this is the the only part of the reading stats that is exclusive to synced (kobo-bought) kepubs.
The stats page shown in ElWorm's pic in post #7 is available for sideloaded books too (both kepub and epub), but the chapter progress bar only works for kepubs (it is still shown for epubs, but is not accurate).