If you are talking about the largest chrome shaft that comes out of the the outer housing, then yes, it has to be straight.

How would you expect it to move back and forth or in and out of the housing, that is straight and "not" made like a banana?

You need to ask a lot harder question, like does the rack make the car go around corner or it the wheels? @(:<>)

You identify the rack by what type of rubber boots it has. Does it have little ends or big ends where the clamps go. Please do ask me to tell which end would be considered a big end! (?)

Got a Bentley manual?
Phil