42RH Accumulator springs

Please can someone explain why some 42RH transmissions have a smaller spring under the accumulator piston and others don't? I thought it might be linked to the later versions that have a boost pipe outside the valve body but not so sure now. My transmission is now apart for a rebuild. It only has the larger spring and I would like to know if this is how it left the factory. If not, whether to put the smaller spring back in or leave as is.