do you need the cortiner uprights when building this kit car because i know you need the hubs

I'm not building an Indy, so maybe somebody that knows more about them will say something, but I thought the Indy used Sierra stuff, not the Cortina?

Sierra front uprights and hubs which are modified on exchange along with the steering rack when you pick up your Kit. Don't forget them or you won't be given the modified ones!