Judgments and orders passed by an Appellate Court upon an appeal shall be final, except in the cases provided for in section 377, section 378, sub-section (4) of section 384 or Chapter XXX:
    Provided that notwithstanding the final disposal of an appeal against conviction in any case, the Appellate Court may hear and dispose of, on the merits,
        (a) an appeal against acquittal under section 378, arising out of the same case, or
        (b) an appeal for the enhancement of sentence under section 377, arising out of the same case.