I wonder a bit why someone would store private keys in hex format which is a rather error prone format.
Back when WIF isn't introduced yet (
included in #574), some third-party scripts/tool exports prvKeys in HEX.
The only chance that OP's list are prvKeys is if it's older than that commit, else, it's as the majority said.
It would have to be a backup generated by a different wallet software from Bitcoin Core. If OP is not finding anything from this address then it could mean that there's a (different) HD wallet derivation path involved.
He should see if the data is a valid Armory or Multibit backup.