It is not appropriate to place information on official documents that is not factual. It is wrong to place counseling dates on an NCOER if these dates did not occur as indicated on the evaluation report.
If the performance counseling sessions did not occur, the rater should remove the falsified dates. The senior rater then makes a comment as to why the counseling was not conducted IAW AR 623-3.
Your signature on the NCOER means that you agree the dates of counseling are correct among other things. For an in-depth explanation see: What does my signature mean on the NCOER? or consult AR 623-3.
See Can my squad leader give me a backdated counseling statement? for additional information about backdated counseling statements.