In the event no final pre-trial conference is held, the court may enter an order directing the parties to file with the court and serve on all opposing counsel, or upon parties not represented by counsel, a list of all exhibits to be offered at trial and a list of the names and addresses of all witnesses which such party may call to testify at the trial, except for impeachment witnesses and exhibits. Any exhibits or witnesses discovered after such disclosure shall immediately be disclosed to the court and opposing counsel by filing and service stating the date upon which the same was discovered. Failure to comply with this rule may be grounds for excluding an exhibit from admission into evidence or for excluding a witness from testifying in the trial of the action. Provided the court, for good cause shown and in order to prevent injustice may permit additional exhibits to be used or additional witnesses to testify at the trial.