"Counterfeit Check Stamp" At Teller Line

I am not aware of any bank that has adopted such a practice. In fact, I can't recommend it, since labeling a check as "counterfeit" could expose the bank to wrongful dishonor claims if a teller errs and uses the stamp on a legitimate check. Unless the purported issuer of the check has provided an affidavit that the check is a counterfeit, it would be a better practice to refuse payment at the teller line with a statement that the signature on the check doesn't appear to agree with the bank's records.