Window regulator roller replacement

[tucsonjwt]

My 83 C20 needs the plastic rollers for the power window regulators replaced. They are riveted in place on the end of the regulator arms. Where can I get replacement rollers and how are they replaced? Can you just pry off the plastic roller from the rivet and snap on a new one, or does the rivet have to be drilled out. If the rivet has to come out, how is that removed and replaced?
My AC Delco power window replacement lasted only about 3 years. I think the stuck rollers overheated/overworked the window. I probably have to do both windows.
Thanks.