GM 525 Steering box help

I have a new 525 GM steering box and I have a question. Is the pitman arm shaft that comes out of the steering box tapered? My pitman arm will only slide on easily in one position and it appears that it needs to have the drop in other position. So I need to know if it is tapered so I can order another pitman arm that has the drop in the opposite direction. Any help would be appreciated. Thanks

 

They are tapered but ever so slightly.