Yes, a sign of a gazetted officer in the photocopies of your required documents is required for KCET. You have to show the documents during admission. It is a mandatory failing of which you will not be able to take admission. You can sign them from the BEO or DDPI office or a continual educator of a govt college, a principal of any govt school having at least up to class 10, the principal of any degree institute, registrar and vice Chancellor of universities. Any  Grade-A official like SDM, DM/DC, ETO, Tehsildar, DSP, SP etc, any govt clinic M.D, any govt veterinary medic, an MLA or an MP can sign your papers. Remember, to take the original documents with you when to visit one of these officials.

Regards.