I tore back into it today, and the inner race WAS missing. Whoever took it apart prior to me must have just missed that piece in reassembly. I reused the outer bearing, but replaced the plastic retainer, ball bearings, and inner race with the new GM bearing parts. Put everything back together and the play is completely gone! I also replaced the turn signal cam while I was in there, since I didn't replace that last time (just did the blinker switch and multi-function switch/rod before). Thanks again to all who posted information - very happy to have this fixed now.