The meaning of the episode names in "The Promised Neverland"
Yes, the episode titles are dates. For example the first episode's title is 121045, which means 12th October, and it corresponds to the date that Conny leaves to "get adopted". You can see the date on a calendar in the first episode: 



Similarly, the second episode is titled 131045, which is the day after Conny leaves, and so on...