But like, if, 120 million years from now, there is no life that has an analogue to poop, would they be able to guess that the coprolites they discovered were th

But like, if, 120 million years from now, there is no life that has an analogue to poop, would they be able to guess that the coprolites they discovered were the waste products of a lifeform? Why couldn't it just be the remains of the body parts of ancient life? Like what if oil/petroleum is actually the poop of ancient lifeforms, but we assume it's the remains of the lifeforms themselves.