Actually if they are exactly or nearly-exactly alike it's highly suspicious - two people witnessing the same event never give the same description, and the effect is magnified when the witness is surprised or under stress. If the logs show major discrepencies, though (e.g. Log 1 saying "No combat," and Log 2 saying "We exchanged fire with an entrenched brigade."), then one or both entries are lies.
Especially if the logs were rewritten by Lehman