Hold on a minute... I thought this was about the Cordovox ORGAN!
Given that the post was about a Cordovox organ, I got all confused! (not hard to do at my age!)
mine was the Cordovox accordion ... when I played it electronically - for all the different organ 'voices', the bellows did not have to be 'pumped' - I just placed the accordion on top of the Rhodes and played the keys when I wanted organ sounds ...