Yes The appraisal report needs the seal of the appraisal institution and the signature of the appraiser with professional qualifications, and the appraisal report issued is true. If there is no signature, the appraisal report is invalid, and the appraisal report given by the bank is invalid without the signature of the appraiser. You can bring a lawsuit to the court. The appraisal report is a written report made by the appraisal institution according to a specific purpose, following the laws and standards of the public, following legal procedures and using scientific methods to evaluate and estimate assets and projects.