Ikoflex Ic meter, Selenium or Cds ?

I've heard that the meter type was changed partway through the production period, but the various on-line copied Instructions I've found for the Ic omit details of where the Cds meter's battery is and/or how to change it .

As far as I know the Ikoflex 1c meter always was selenium, Zeiss tended to stick with Selenium certainly till the sixties,Richard