broken pins on a Manhattan shower door roller

A shower door installed by the prior homeowner (early 2000s) has brackets with two rollers, which have the same look and dimensions as Swisco part 10-071. Three of the 4 pins that go into the wheels have broken. 

If I buy a new part, is it possible for me to remove the new wheels and to insert the bracket pins into the existing wheels? Thanks.

Thank you. Yes, the pegs are definitely bad on this existing roller. I was hoping that I could keep the track and remaining rollers intact. It appears not. Thanks for the advice, and I'll give it a try after my order arrives.