Hi Eva,
Thank you for finding these records! I agree that it's pretty convincing that the records are for my migrating ancestor, Eric/k Peterson, based on the exact birth date, the parents' names, and the remark that he calls himself Pettersson.
I don't have an ArkivDigital account, but I will do more research using my Ancestry World subscription and the records at Riksarkivet.
Thanks, again!